Low Bone Mineral Density as a Risk Factor for Liver Cirrhosis: A Prospective Cohort Study

CONTEXT

Bone metabolism interplays with liver metabolism, also known as the liver-bone axis. Osteoporosis is a common complication of cirrhosis, but whether bone mineral density (BMD) can predict cirrhosis development is unknown.

OBJECTIVE

This study aims to investigate the relationship between BMD and the risk of incident cirrhosis in the Hong Kong Osteoporosis Study (HKOS).

METHODS

BMD was measured at the lumbar spine, femoral neck, total hip, and trochanter of 7,752 participants by the dual-energy X-ray absorptiometer (DXA), and the incidence of cirrhosis and mortality were followed by linking to the territory-wide electronic health records database. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% CI.

RESULTS

With a median follow-up of 18.43 years, 42 incident cirrhosis were identified. Higher BMD T-scores at the femoral neck, total hip and trochanter were significantly associated with a reduced risk of cirrhosis (femoral neck: HR 0.56, 95% CI 0.39 to 0.82; total hip: HR 0.60, 95% CI 0.44 to 0.82; trochanter: HR 0.63, 95% CI 0.46 to 0.88). Similar associations were observed in participants without risk factors of cirrhosis at the baseline and further adjusting for the baseline level of alkaline phosphatase, albumin, and alanine transaminase. Consistent relationships in multiple sensitivity analyses suggest the robustness of the results.

CONCLUSION

Low BMD could be a novel risk factor and early predictor for cirrhosis, with consistent associations observed in multiple sensitivity analyses.

Consensus statement on the management of hyperkalaemia-An Asia-Pacific perspective

Hyperkalaemia is an electrolyte imbalance that impairs muscle function and myocardial excitability, and can potentially lead to fatal arrhythmias and sudden cardiac death. The prevalence of hyperkalaemia is estimated to be 6%-7% worldwide and 7%-10% in Asia. Hyperkalaemia frequently affects patients with chronic kidney disease, heart failure, and diabetes mellitus, particularly those receiving treatment with renin-angiotensin-aldosterone system (RAAS) inhibitors. Both hyperkalaemia and interruption of RAAS inhibitor therapy are associated with increased risks for cardiovascular events, hospitalisations, and death, highlighting a clinical dilemma in high-risk patients. Conventional potassium-binding resins are widely used for the treatment of hyperkalaemia; however, caveats such as the unpalatable taste and the risk of gastrointestinal side effects limit their chronic use. Recent evidence suggests that, with a rapid onset of action and improved gastrointestinal tolerability, novel oral potassium binders (e.g., patiromer and sodium zirconium cyclosilicate) are alternative treatment options for both acute and chronic hyperkalaemia. To optimise the care for patients with hyperkalaemia in the Asia-Pacific region, a multidisciplinary expert panel was convened to review published literature, share clinical experiences, and ultimately formulate 25 consensus statements, covering three clinical areas: (i) risk factors of hyperkalaemia and risk stratification in susceptible patients; (ii) prevention of hyperkalaemia for at-risk individuals; and (iii) correction of hyperkalaemia for at-risk individuals with cardiorenal disease. These statements were expected to serve as useful guidance in the management of hyperkalaemia for health care providers in the region.

Serum Tsukushi Level Is Associated With the Severity of Liver Fibrosis Independent of Type 2 Diabetes

BACKGROUND AND AIMS

Tsukushi (TSK) is a recently identified hepatokine, and we aimed to investigate the association between systemic TSK and the severity of nonalcoholic fatty liver disease (NAFLD) in subjects with and without type 2 diabetes mellitus (DM).

METHODS

Three hundred ninety-three DM and 289 without DM individuals were recruited for transient elastography assessment to determine liver steatosis and fibrosis. Serum TSK was measured by ELISA. The presence of NAFLD was defined as controlled attenuation parameter ≥ 248 dB/m.

RESULTS

NAFLD was present in 276 (70.2%) and 129 (44.6%) subjects with and without DM respectively, and they had higher serum TSK levels than those without NAFLD [DM group: 91.0 ng/mL (61.7-133.8) vs 82.5 (60.9-118.5), P < .01 respectively; without DM group: 97.1 ng/mL (69.3-148.6) vs 80.8 (53.4-111.6) respectively, P < .01]. Univariate analysis showed that serum TSK significantly correlated with the degree of steatosis and fibrosis both in subjects with and without DM. On multivariable regression analysis, only liver stiffness and estimated glomerular filtration rate were significant determinants of TSK level, and the relationship was independent of diabetes and serum adiponectin. Out of 405 subjects with NAFLD, 49 had either advanced fibrosis or cirrhosis. The area under receiver operating characteristic curve of serum TSK to indicate advanced fibrosis or cirrhosis was 0.70 (95% CI .62-.77), which was significantly better than that of fibrosis-4 index, 0.64 (95% CI .55-.72), P < .05.

CONCLUSION

Serum TSK levels were increased in subjects with NAFLD and reflected the severity of liver fibrosis.

Recalibration of a Non-Laboratory-Based Risk Model to Estimate Pre-Diabetes/Diabetes Mellitus Risk in Primary Care in Hong Kong

INTRODUCTION/OBJECTIVES

A non-laboratory-based pre-diabetes/diabetes mellitus (pre-DM/DM) risk prediction model developed from the Hong Kong Chinese population showed good external discrimination in a primary care (PC) population, but the estimated risk level was significantly lower than the observed incidence, indicating poor calibration. This study explored whether recalibrating/updating methods could improve the model's accuracy in estimating individuals' risks in PC.

METHODS

We performed a secondary analysis on the model's predictors and blood test results of 919 Chinese adults with no prior DM diagnosis recruited from PC clinics from April 2021 to January 2022 in HK. The dataset was randomly split in half into a training set and a test set. The model was recalibrated/updated based on a seven-step methodology, including model recalibrating, revising and extending methods. The primary outcome was the calibration of the recalibrated/updated models, indicated by calibration plots. The models' discrimination, indicated by the area under the receiver operating characteristic curves (AUC-ROC), was also evaluated.

RESULTS

Recalibrating the model's regression constant, with no change to the predictors' coefficients, improved the model's accuracy (calibration plot intercept: -0.01, slope: 0.69). More extensive methods could not improve any further. All recalibrated/updated models had similar AUC-ROCs to the original model.

CONCLUSION

The simple recalibration method can adapt the HK Chinese pre-DM/DM model to PC populations with different pre-test probabilities. The recalibrated model can be used as a first-step screening tool and as a measure to monitor changes in pre-DM/DM risks over time or after interventions.

Association of Sodium-Glucose Cotransporter 2 Inhibitor vs Dipeptidyl Peptidase-4 Inhibitor Use With Risk of Incident Obstructive Airway Disease and Exacerbation Events Among Patients With Type 2 Diabetes in Hong Kong

IMPORTANCE

Patients with diabetes are at higher risk for obstructive airway disease (OAD). In recent meta-analyses of post hoc analyses of cardiorenal trials, sodium-glucose cotransporter 2 inhibitors (SGLT2Is) were suggested to reduce the risk of OAD adverse events. However, a clinical investigation of this association is warranted.

OBJECTIVE

This study aimed to investigate the association of SGLT2I use vs dipeptidyl peptidase-4 inhibitor (DPP4I) use with OAD incidence and exacerbation events in patients with type 2 diabetes.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective population-based cohort study used electronic health data from a territory-wide electronic medical database in Hong Kong. Data were collected for patients with type 2 diabetes who were prescribed SGLT2Is or DPP4Is between January 1, 2015, and December 31, 2018. Patients were followed for a median of 2.2 years between January 1, 2015, and December 31, 2020. A prevalent new-user design was adopted to match patients based on previous exposure to the study drugs. Propensity score matching was used to balance baseline characteristics.

EXPOSURES

Patients with type 2 diabetes using SGLT2Is (exposure of interest) or DPP4Is (active comparator).

MAIN OUTCOMES AND MEASURES

The main outcomes were the first incidence of OAD and the count of OAD exacerbations. The risk of incident OAD was estimated using a Cox proportional hazards regression model. The rate of exacerbations was estimated using zero-inflated Poisson regression. Statistical analysis was performed on November 13, 2022.

RESULTS

This study included 30 385 patients. The propensity score-matched non-OAD cohort (incidence analysis) consisted of 5696 SGLT2I users and 22 784 DPP4I users, while the matched OAD cohort (exacerbations analysis) comprised 381 SGLT2I users and 1524 DPP4I users. At baseline, 56% of patients in the non-OAD cohort were men and the mean (SD) age was 61.2 (9.9) years; 51% of patients in the OAD cohort were men and the mean age was 62.2 (10.8) years. Compared with DPP4I use, SGLT2I use was associated with a lower risk of incident OAD (hazard ratio, 0.65 [95% CI, 0.54-0.79]; P < .001) and a lower rate of exacerbations (rate ratio, 0.54 [95% CI, 0.36-0.83]; P = .01). The associations were consistent in sex subgroup analysis.

CONCLUSIONS AND RELEVANCE

The findings of this retrospective cohort study of patients with type 2 diabetes in Hong Kong suggest that SGLT2I use was associated with a reduced risk of incident OAD and a lower rate of exacerbations in a clinical setting compared with DPP4I use. These findings further suggest that SGLT2Is may provide additional protective effects against OAD for patients with type 2 diabetes and that further investigation is warranted.

Unravelling genetic causality of haematopoiesis on bone metabolism in human

OBJECTIVE

Haematopoiesis was shown to regulate bone metabolism in in vivo studies. However, whether haematopoiesis has causal effects on bone health has never been investigated in humans. We aimed to evaluate the causal relationships of blood traits with bone mineral density (BMD) and fracture.

DESIGN AND METHODS

Using two-sample Mendelian randomization, causal relationship of 29 blood traits with estimated BMD (eBMD), total body BMD (TBBMD), lumbar spine BMD (LSBMD), femoral neck BMD (FNBMD) and fracture were evaluated by inverse-variance weighted (IVW) method and multiple sensitivity analyses. Relevant genetic data were obtained from the largest possible publicly available genome-wide association studies.

RESULTS

Eight genetically determined red blood cell traits showed positive causal effects on eBMD, with beta estimates ranging from 0.009 (mean corpuscular haemoglobin) to 0.057 (haemoglobin concentration), while three white blood cell traits, including lymphocyte count (beta: -0.020; 95% CI: -0.033 to -0.007), neutrophil count (beta: -0.020; 95% CI: -0.035 to -0.006) and white blood cell count (beta: -0.027; 95% CI: -0.039 to -0.014), were inversely associated with eBMD. Causal effects for six of these blood traits were validated on TBBMD, LSBMD, FNBMD and/or fracture. The association of reticulocyte count (beta: 0.040; 95% CI: 0.016 to 0.063), haemoglobin (beta: 0.058; 95% CI: 0.021 to 0.094) and mean corpuscular haemoglobin concentration (beta: 0.030; 95% CI: 0.007 to 0.054) with eBMD remained significant in multivariable IVW analyses adjusted for other blood traits.

CONCLUSION

This study provided evidence that haematopoietic system might regulate the skeletal system in humans and suggested the possible pathophysiology of bone diseases among people with haematological diseases.

SIGNIFICANCE STATEMENT

We conducted a novel Mendelian randomization study investigating the causal relationship of blood cells with bone mineral density. Red and white blood cell traits have positive and inverse causal relationship with bone mineral density, respectively, suggesting a potential link of haematopoietic system with the skeletal system in humans. Current findings suggest individuals with related haematological diseases, such as anaemia and leukocytosis, may have a lifelong increased risk of osteoporosis and/or fracture. Given that complete blood count is commonly performed in clinical setting, whether complete blood count can be used to predict fracture risk warrants further investigation.

Hip Fracture as a Predictive Marker for the Risk of Dementia: A Population-Based Cohort Study

OBJECTIVES

This study aimed to investigate the association between hip fracture and the risk of dementia.

DESIGN

A retrospective real-world propensity score-matched cohort study was conducted using the real-world hip fracture cohort (RHFC).

SETTING AND PARTICIPANTS

Electronic health record data from the Clinical Data Analysis and Reporting System (CDARS) in Hong Kong were used. A total of 52,848 patients aged ≥65 years and with at least an event of fall from 2006 to 2015 were included in the RHFC.

METHODS

The incidence of fall, hip fracture, and dementia was determined using their International Classification of Diseases, Ninth Revision (ICD-9) codes. Competing risk regression models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

Hip fracture was associated with an increased risk of dementia (HR 1.09, 95% CI 1.04-1.15, P < .001). The subgroup analysis showed that association was significant in women but not in men.

CONCLUSIONS AND IMPLICATIONS

Hip fracture was associated with the increased risk of dementia among older adults. Further studies investigating the potential roles of hip fracture in the development of dementia could benefit the management of both conditions in older adults.

Cholesterol efflux capacity of HDL was not associated with cognitive decline and brain structures in older people with diabetes mellitus

Aims/Introduction

To examine the association between cholesterol efflux capacity (CEC) of serum high‐density lipoprotein (HDL) and cognitive function and brain structures in older people with diabetes mellitus.

Materials and Methods

Participants of a randomized placebo‐controlled trial of 27‐month vitamin B₁₂ supplementation in older people with diabetes mellitus, which showed no effect on cognition, were further followed up at month 72. Cognitive tests included the Clinical Dementia Rating scale, Neuropsychological Test Battery in memory, executive function and psychomotor speed. Brain magnetic resonance imaging scans were carried out in a subset at baseline, month 27 and month 45. Fasting serum at baseline, month 9, month 27 and month 72 were analyzed for adenosine triphosphate‐binding cassette transporter A1‐mediated CEC of HDL and apolipoprotein A1 (ApoA1).

Results

Serum HDL cholesterol at baseline was associated with better executive and memory function at follow up. Serum ApoA1 was associated with a better memory Z‐score at month 18. Serum CEC and ApoA1 were not associated with Clinical Dementia Rating scale, Neuropsychological Test Battery, hippocampal volume and white matter disease on magnetic resonance imaging at baseline and whole brain atrophy rates. They were also not associated with cognitive function at month 27 and 72 on multilevel modeling. CEC and ApoA1 decreased significantly from baseline to month 27. Faster decliners in CEC had a greater increase in brain peak width of skeletonized mean diffusivity.

Conclusions

Higher serum HDL cholesterol was associated with more favorable changes in memory and executive function in older people with diabetes mellitus. However, this was not due to CEC or ApoA1. A decline in CEC was associated with small vessel disease in the brain.

Association Between SGLT2 Inhibitors vs DPP4 Inhibitors and Renal Outcomes Among Patients With Type 2 Diabetes

CONTEXT

Diabetic kidney disease is a major burden among diabetic patients. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) were shown to reduce renal outcomes in clinical trials and real-world studies. However, head-to-head comparisons with individual classes of glucose-lowering agents warranted further investigation.

OBJECTIVE

This work aimed to investigate the associations between SGLT2is use vs dipeptidyl peptidase-4 inhibitors (DPP4is) use and 4 renal outcomes: end-stage renal disease (ESRD), albuminuria, acute renal failure (ARF), and the rate of estimated glomerular filtration rate (eGFR) change using a territory-wide electronic medical database in Hong Kong.

METHODS

For this retrospective cohort study, the "prevalent new-user" design was adopted to account for previous exposure to study drugs. Propensity score matching was used to balance baseline characteristics. Electronic health data of type 2 diabetes patients using SGLT2is and DPP4is between 2015 and 2018 were collected.

RESULTS

The matched cohort consisted of 6333 SGLT2is users and 25 332 DPP4is users, with a median follow-up of 3.8 years. Compared to DPP4is, SGLT2is use was associated with lower risks of ESRD (hazard ratio [HR]: 0.51; 95% CI, 0.42-0.62; P < .001) and ARF (HR: 0.59; 95% CI, 0.48-0.73; P < .001), and a slower decline in eGFR. The associations remained statistically significant among patients with or without rapid eGFR decline and patients who added or switched to SGLT2is from DPP4is. The association with albuminuria was inconsistent across analyses.

CONCLUSION

Compared to DPP4is, SGLT2is use was associated with reduced risks of ESRD and ARF, and a slower eGFR decline in a real-world setting. The associations remained statistically significant in patients with or without preindex rapid eGFR decline.

A study on clinical outcomes of Rathke's cleft cyst in patients managed conservatively

OBJECTIVES

The primary objective was to investigate the clinical presentation, hormonal dysfunction, imaging characteristics and natural history of RCCs that were managed conservatively. Secondary objective was to identify factors associated with cyst progression.

METHODS

A retrospective review of patients with the clinical diagnosis of RCC-identified from word search from radiology reports that were followed up from January 1999 to March 2019 was performed. The demographics, clinical data, radiological features and outcomes were reviewed and analyzed.

RESULTS

105 patients were identified with a median follow up of 6 years. 68 patients (64.8%) were managed conservatively from diagnosis till last follow up while 37 patients (35.2%) underwent surgery, with 26 operated at time of diagnosis and 11 operated upon monitoring. For patients managed conservatively from diagnosis till last follow up, incidental finding was the most common presentation. 19.1% had either one or more axes of hormonal dysfunction, with hypogonadism and hypocortisolemia being the commonest ones. Imaging features were variable. 66.2% of patients had T2W hyperintensity on MRI. Pathognomonic feature of intracystic nodule was present in only 14.7% of patients. Among the 79 patients with repeated MRI imaging (68 from conservative group and 11 from surgical group), 32.9% of patients developed cyst progression while 67.1% had either static disease or regression in size of RCC. Median time to progression of cyst was 14 months. Longer median follow up duration and presence of pituitary stalk displacement at presentation were associated with cyst progression. Only one patient developed new endocrine dysfunction.

CONCLUSION

2/3 of the RCCs had static disease or even regression in the size of the cyst. They rarely gave rise to additional endocrine dysfunction by adopting observant approach. Cyst progression was demonstrated in 1/3 of patients. Conservative treatment remained a reasonable treatment for patients without significant symptoms.

Association Between SGLT2 Inhibitors vs DPP-4 Inhibitors and Risk of Pneumonia Among Patients With Type 2 Diabetes

CONTEXT

Patients with diabetes are at a higher risk of pneumonia and pneumonia mortality. Sodium glucose co-transporter 2 inhibitors (SGLT2is), the latest class of glucose-lowering agents, were shown to reduce the risk of pneumonia in clinical trials. However, the real-world effectiveness of SGLT2is on the risk of pneumonia is largely unknown.

OBJECTIVE

To investigate the associations between SGLT2is use and the risk of pneumonia and pneumonia mortality compared with dipeptidyl peptidase-4 inhibitors (DPP4is) using an electronic medical database in Hong Kong.

DESIGN

A retrospective cohort study. The "prevalent new-user" design was adopted to account for the previous exposure to the study drugs being compared. Propensity score (PS) matching (1:4) was used to balance the baseline characteristics of the 2 groups.

SETTING AND PARTICIPANTS

Electronic health data of type 2 diabetes patients using SGLT2is and DPP4is between 2015 and 2018 was collected from the Clinical Data Analysis and Reporting System.

MAIN OUTCOME MEASURES

Pneumonia incidence and mortality.

RESULTS

The PS-matched cohort consisted of 6664 users of SGLT2is and 26 656 users of DPP4is, with a mean follow-up of 3.8 years. Poisson regression showed that SGLT2is use was associated with lower risk of pneumonia compared with DPP4is with an absolute rate difference of 4.05 per 1000 person-years (95% CI, 2.61-5.51). The corresponding incidence rate ratio was 0.71 (95% CI, 0.62-0.81). Similar reduction in risk of pneumonia death was observed (hazard ratio 0.57; 95% CI, 0.42-0.77).

CONCLUSION

Compared with DPP4is, SGLT2is use was associated with a reduced risk of pneumonia and pneumonia mortality in a real-world setting.

Immediate Risk for Cardiovascular Events in Hip Fracture Patients: A Population-Based Cohort Study

BACKGROUND

Emerging evidence showed that bone metabolism and cardiovascular diseases (CVD) are closely related. We previously observed a potential immediate risk of cardiovascular mortality after hip fracture. However, whether there is an immediate risk of cardiovascular events after hip fracture is unclear. The aim of this study was to evaluate the risk for major adverse cardiovascular events (MACEs) between patients having experienced falls with and without hip fracture.

METHODS

This retrospective population-based cohort study used data from a centralized electronic health record database managed by Hong Kong Hospital Authority. Patients having experienced falls with and without hip fracture were matched by propensity score (PS) at a 1:1 ratio. Adjusted associations between hip fracture and risk of MACEs were evaluated using competing risk regression after accounting for competing risk of death.

RESULTS

Competing risk regression showed that hip fracture was associated with increased one-year risk of MACEs (hazard ratio [HR], 1.27; 95% CI, 1.21 to 1.33; p<0.001), with a 1-year cumulative incidence difference of 2.40% (1.94% to 2.87%). The HR was the highest in the first 90-day after hip fracture (HR of 1.32), and such an estimate was continuously reduced in 180-day, 270-day, and 1-year after hip fracture.

CONCLUSIONS

Hip fracture was associated with increased immediate risk of MACEs. This study suggested that a prompt evaluation of MACE among older adults aged 65 years and older who are diagnosed with hip fracture irrespectively of cardiovascular risk factors may be important, as early management may reduce subsequent risk of MACE.

Long-term Outcome of Short-course High-dose Glucocorticoids for Severe Acute Respiratory Syndrome (SARS): A 17-Year Follow-up in SARS Survivors

Use of high-dose glucocorticoids for coronavirus disease 2019 (COVID-19; caused by SARS-CoV-2) is controversial because of safety concerns. We examined long-term consequences in severe acute respiratory syndrome (SARS; caused by SARS-CoV-1) survivors. Results showed that high-dose glucocorticoids greatly increased long-term risk of avascular necrosis, but not other major diseases.

Identification of ANXA2 as a Potential Susceptibility Gene for Diabetic Retinopathy in a Genome-Wide Association Analysis in Chinese Patients With Type 2 Diabetes Mellitus

Background: Diabetic retinopathy (DR) is the most frequent microvascular complication of type 2 diabetes mellitus (T2DM). Variation in allele frequencies between different ethnic groups may influence the detectability of the risk variants in different populations. It is therefore important to conduct ethnic-specific association analysis to discover novel loci. The major objective of this study was to conduct a 2-stage genome-wide association study (GWAS) to identify novel susceptibility single nucleotide polymorphisms (SNPs) for sight-threatening DR in Chinese patients with T2DM.

Methods and Materials: The discovery stage consisted of 681 STDR cases and 758 non-STDR controls of Southern Chinese ancestry. The Illumina Infinium Asian Screening Array (ASA) was used for genotyping of the subjects. Imputation was performed using the TOPMed Imputation Server. SNPs with minor allele frequency (MAF) <0.01 and INFO score <0.3 were excluded. Single variant association analysis was performed in SNPTEST using the multiple logistic regression model with adjustment for age, gender, duration of diabetes, hypertension, hemoglobin A1c (HbA1c), and the first five principal components. The replication cohort was comprised of an independent sample set of 278 STDR cases and 834 non-STDR controls. Meta-analysis of the association results of the discovery and replication stages was conducted using the “GWAMA” software. The inverse variance fixed-effect method was used to meta-analyze the summary statistics of the two stages.

Results: In the discovery stage, the strongest association was detected at an intronic variant of ANXA2 (P=1.87x10^-7; OR[95%CI]:1.59[1.31–1.96]). Ninety-three SNPs showing suggestive associations (P<5x10^-5) with STDR in the discovery stage were selected for replication. In the meta-analysis of the two stages, the ANXA2 SNP again showed the strongest association with STDR (P=2.18x10^-6; OR[95%CI]: 1.45[1.24–1.70]). ANXA2 encodes the annexin A2 which has been shown to play an important role in promoting angiogenesis. An intronic SNP of DOC2B, a tumor suppressor gene that exhibits functions in cell proliferation and migration, also demonstrated a marginal association with STDR (P=5.17x10^-6; OR[95%CI]: 1.41[1.22–1.63]). Two intergenic variants located at the RPL31P11-FCRLA (P=7.25x10^-6; OR[95%CI]: 1.54[1.27–1.85]) and COL6A1-COL6A2 (P=9.60x10^-6; OR[95%CI]: 0.73[0.63–0.84]) loci also showed suggestive associations with STDR.

Conclusion: Several novel STDR-associated genetic variants were identified in this genome-wide association study. Our findings have shed new lights on the genetic basis of STDR in Chinese patients with T2DM. Further validation in independent cohorts to validate our findings are warranted.

Acknowledgements: This study was supported by the Research Grant Council – General Research Fund of Hong Kong (Ref no.: 17118119).

Insights From Prospective Follow-up of Thyroid Function and Autoimmunity Among Covid-19 Survivors

Objective: Occurrence of Graves’ disease and Hashimoto’s thyroiditis after coronavirus disease 2019 (COVID-19) raised the concern about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggering thyroid autoimmunity. Uncertainties remain regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors. We carried out a prospective study to characterize the evolution of thyroid function and autoimmunity among COVID-19 survivors. Method: Consecutive adult patients, without known thyroid disorders, admitted to Queen Mary Hospital for confirmed COVID-19 from 21 July to 21 September 2020 were included. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and anti-thyroid antibodies were measured on admission and at 3 months. Positive anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) was defined by >100 units. Results: Among 200 COVID-19 survivors, 122 had reassessment thyroid function tests (TFTs) (median age: 57.5 years; 49.2% men). Baseline characteristics of patients who did and did not have reassessment were comparable. Among the 20 patients with baseline abnormal TFTs on admission, mostly low fT3, 15 recovered. Of the 102 patients with normal TFTs on admission, two (2.0%) had new onset abnormal TFTs, which may represent TFTs in different phases of thyroiditis (one had mildly elevated TSH 5.8 mIU/L, with normal fT4 [16 pmol/L] and fT3 [4.3 pmol/L], the other had mildly raised fT4 25 pmol/L with normal TSH [1.1 mIU/L] and fT3 [4.7 pmol/L]). Among 104 patients with anti-thyroid antibody titers reassessed, we observed increases in anti-TPO (baseline: 28.3 units [IQR 14.0-67.4] vs reassessment: 35.0 units [IQR: 18.8-99.0]; p<0.001) and anti-Tg titers (baseline: 6.6 units [IQR 4.9-15.6] vs reassessment: 8.7 units [IQR: 6.6-15.4]; p<0.001), but no change in anti-TSHR titer (baseline: 1.0 IU/L [IQR: 0.8-1.2] vs reassessment: 1.0 IU/L [IQR: 0.8-1.3]; p=0.486). Of the 82 patients with negative anti-TPO at baseline, 16 had significant interval increase in anti-TPO titer by >12 units (2×6 [precision of the anti-TPO assay in normal range being 6 units per SD]), of these, four became anti-TPO positive. Factors associated a significant increase in anti-TPO titer included worse baseline clinical severity (p=0.018), elevated C-reactive protein during hospitalization (p=0.033), and higher baseline anti-TPO titer (p=0.005). Conclusion: Majority of thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis could occur during convalescence, though uncommon. Importantly, we provided the novel observation of an increase in anti-thyroid antibody titers post-COVID-19, suggesting the potential of SARS-CoV-2 in triggering thyroid autoimmunity, which warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.

Treatment with direct oral anticoagulants or warfarin and the risk for incident diabetes among patients with atrial fibrillation: a population-based cohort study

Background

Diabetes mellitus is a common comorbidity of atrial fibrillation (AF), which can complicate the management of AF. The pharmacology of oral anticoagulants (OACs) have been implicated in pathogenesis of diabetes, but the relationship between different OACs and risk of diabetes remains unexamined. This study aimed to evaluate the risk of diabetes with use of different OACs in AF patients.

Methods

Population-based retrospective cohort study using an electronic healthcare database managed by the Hong Kong Hospital Authority. Patients newly diagnosed with AF from 2014 through 2018 and prescribed OACs were included and followed till December 31, 2019. Inverse probability of treatment weighting based on the propensity score (PS) is used to address potential bias due to nonrandomized allocation of treatment. The risks ofdiabetes were compared between different new OAC users using propensity score-weighted cumulative incidence differences (CID).

Results

There were 13,688 new users of OACs (warfarin: n = 3454; apixaban: n = 3335; dabigatran: n = 4210; rivaroxaban: n = 2689). The mean age was 75.0 (SD, 11.2), and 6,550 (47.9%) were women. After a median follow-up of 0.93 years (interquartile range, 0.21–1.92 years), 698 incident diabetes cases were observed. In Cox-regression analysis, dabigatran use was significantly associated with reduced risk of diabetes when compared with warfarin use [HR 0.69 (95% CI 0.56–0.86; P < 0.001)], with statistically insignificant associations observed for use of apixaban and rivaroxaban. The corresponding adjusted CIDs at 2 years after treatment with apixaban, dabigatran, and rivaroxaban users when compared with warfarin were − 2.06% (95% CI − 4.08 to 0.16%); − 3.06% (95% CI − 4.79 to − 1.15%); and − 1.8% (− 3.62 to 0.23%). In head-to-head comparisons between women DOAC users, dabigatran was also associated with a lower risk of diabetes when compared with apixaban and rivaroxaban.

Conclusions

Among adults with AF receiving OACs, the use of dabigatran had the lowest risk of diabetes when compared with warfarin use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01263-0.

Carbamylated HDL and Mortality Outcomes in Type 2 Diabetes

OBJECTIVE

Carbamylation is part of the aging process and causes adverse changes in the structure and function of proteins. Lipoproteins are subjected to carbamylation. We investigated the usefulness of carbamylated HDL as a prognostic indicator of survival in patients with type 2 diabetes and the association with mortality outcomes.

RESEARCH DESIGN AND METHODS

Baseline plasma carbamylated HDL was measured by ELISA in a cohort of 1,517 patients with type 2 diabetes. The primary outcome was all-cause mortality, and the secondary outcomes were cause-specific deaths, including cardiovascular, renal, infection, and cancer related.

RESULTS

Over a median follow-up of 14 years, 292 patients died, and the mortality rate was 14.5 per 1,000 person-years. Plasma carbamylated HDL level was higher in those with a fatal outcome (46.1 ± 17.8 µg/mL vs. 32.9 ± 10.7; P < 0.01). Patients in the third (hazard ratio [HR] 2.11; 95% CI 1.40-3.17; P < 0.001) and fourth quartiles (HR 6.55; 95% CI 4.67-9.77; P < 0.001) of carbamylated HDL had increased mortality risk. After adjustment for conventional risk factors, elevated carbamylated HDL was independently associated with all-cause mortality (HR 1.39; 95% CI 1.28-1.52; P < 0.001) as well as with all the cause-specific mortalities. Adding plasma carbamylated HDL level improved the power of the multivariable models for predicting all-cause mortality, with significant increments in C index (from 0.78 to 0.80; P < 0.001), net reclassification index, and integrated discrimination improvement.

CONCLUSIONS

Carbamylation of HDL renders HDL dysfunctional, and carbamylated HDL is independently associated with mortality outcomes in patients with type 2 diabetes.

Potential role of fibroblast growth factor 21 in the deterioration of bone quality in impaired glucose tolerance

PURPOSE

Findings on trabecular bone score (TBS), an index of bone quality, have been reported in prediabetes defined by impaired fasting glucose or HbA1c. Here, we assessed the bone mineral density (BMD) and TBS in prediabetes individuals with impaired glucose tolerance (IGT), and investigated the association of these bone parameters with serum levels of fibroblast growth factor 21 (FGF21), a hormone implicated in bone metabolism and with higher levels in IGT.

METHODS

Chinese postmenopausal women aged 55-80 years, without diabetes, were recruited from the Hong Kong Cardiovascular Risk Factor Prevalence Study in 2016-2018. Normal glucose tolerance (NGT) was defined by fasting glucose < 5.6 mmol/L and 2-h plasma glucose (2hG) < 7.8 mmol/L, and IGT by 2hG 7.8-11 mmol/L. Serum levels of FGF21 and other bone metabolism regulators were measured. Insulin sensitivity was assessed by the Matsuda index. Independent determinants of TBS were evaluated using multivariable stepwise linear regression.

RESULTS

173 individuals with NGT and 73 with IGT were included. TBS was lower in those with IGT compared to those with NGT, while BMD was comparable. Individuals with IGT had significantly higher serum FGF21 levels, which in turn showed an independent inverse relationship with TBS, attenuated after inclusion of the Matsuda index. Serum FGF21 levels, however, did not correlate with BMD.

CONCLUSION

Among Chinese postmenopausal women, bone quality was worse in IGT, despite comparable bone density. FGF21 levels showed a significant independent inverse relationship with TBS, partly attributed to insulin resistance. Whether FGF21 contributes to the impaired bone quality in IGT remains speculative.

Development and Validation of a Risk Score to Predict the First Hip Fracture in the Oldest Old: A Retrospective Cohort Study

BACKGROUND

To evaluate whether the common risk factors and risk scores (FRAX, QFracture, and Garvan) can predict hip fracture in the oldest old (defined as people aged 80 and older) and to develop an oldest-old-specific 10-year hip fracture prediction risk algorithm.

METHODS

Subjects aged 80 years and older without history of hip fracture were studied. For the derivation cohort (N = 251, mean age = 83), participants were enrolled with a median follow-up time of 8.9 years. For the validation cohort (N = 599, mean age = 85), outpatients were enrolled with a median follow-up of 2.6 years. A five-factor risk score (the Hong Kong Osteoporosis Study [HKOS] score) for incident hip fracture was derived and validated, and its predictive accuracy was evaluated and compared with other risk scores.

RESULTS

In the derivation cohort, the C-statistics were .65, .61, .65, .76, and .78 for FRAX with bone mineral density (BMD), FRAX without BMD, QFracture, Garvan, and the HKOS score, respectively. The category-less net reclassification index and integrated discrimination improvement of the HKOS score showed a better reclassification of hip fracture than FRAX and QFracture (all p < .001) but not Garvan, while Garvan, but not HKOS score, showed a significant over-estimation in fracture risk (Hosmer-Lemeshow test p < .001). In the validation cohort, the HKOS score had a C-statistic of .81 and a considerable agreement between expected and observed fracture risk in calibration.

CONCLUSION

The HKOS score can predict 10-year incident hip fracture among the oldest old in Hong Kong. The score may be useful in identifying the oldest old patients at risk of hip fracture in both community-dwelling and hospital settings.

Management of Familial Hypercholesterolemia: Current Status and Future Perspectives

Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with premature atherosclerotic cardiovascular disease. Early diagnosis and effective treatment can significantly improve prognosis. Recent advances in the field of lipid metabolism have shed light on the molecular defects in FH and new therapeutic options have emerged. A search of PubMed database up to March 2020 was performed for this review using the following keywords: “familial hypercholesterolemia,” “diagnosis,” “management,” “guideline,” “consensus,” “genetics,” “screening,” “lipid lowering agents.” The prevalence rate of heterozygous FH is approximately 1 in 200 to 250 and FH is underdiagnosed and undertreated in many parts of the world. Diagnostic criteria have been developed to aid the clinical diagnosis of FH. Genetic testing is now available but not widely used. Cascade screening is recommended to identify affected family members, and the benefits of early interventions are clear. Treatment strategy and target is currently based on low-density lipoprotein (LDL) cholesterol levels as the prognosis of FH largely depends on the magnitude of LDL cholesterol-lowering that can be achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment and are cost-effective. Addition of newer medications like PCSK9 inhibitors is able to further lower LDL cholesterol levels substantially, but the cost is high. Lipoprotein apheresis is indicated in homozygous FH or severe heterozygous FH patients with inadequate response to cholesterol-lowering therapies. In conclusion, FH is a common, treatable genetic disorder, and although our understanding of this disease has improved, many challenges still remain for its optimal management.

SUN-372 Deterioration of Bone Microarchitecture in Prediabetes Is Partly Mediated Through Fibroblast Growth Factor 21

Introduction: Prediabetes has been reported to be associated with a worse trabecular bone score (TBS). Fibroblast growth factor 21 (FGF21) levels are raised in prediabetes and other insulin-resistant states, and FGF21 has been reported to be implicated in bone metabolism. We compared the bone mineral density (BMD) and TBS between prediabetes and normoglycemia, and studied the correlation of FGF21 with BMD and TBS. Method: Chinese postmenopausal women aged between 55 and 80 and without type 2 diabetes were recruited from the Hong Kong Cardiovascular Risk Factor Prevalence Study between November 2016 and October 2018. Participants were excluded if they were already on anti-osteoporosis therapy, had secondary causes of osteoporosis, had body mass index (BMI) <15 or >37 kg/m² (when TBS measurement may not be accurate), or had an estimated glomerular filtration rate (eGFR) <30mL/min. They were divided into prediabetes (defined by fasting glucose ≥5.6mmol/L or HbA1c ≥5.7%) and normoglycemia. BMD and TBS were measured by dual-energy X-ray absorptiometry. Serum FGF21 levels were measured with an in-house ELISA kit. Results: 258 participants were included (130 prediabetes and 128 normoglycemia), with a mean age of 61.5±5.1years and mean BMI of 24.2±3.7kg/m². BMD over lumbar spine, femoral neck and total hip were all comparable between prediabetes and normoglycaemia, while TBS was lower in prediabetes (1.27±0.07 vs 1.30±0.07, p=0.007), which remained significant after adjustment for age and BMI. Serum FGF21 levels did not correlate with BMD but inversely correlated with TBS. On multiple linear regression models, serum FGF21 levels showed an independent inverse correlation with TBS (standardized beta -0.13, p=0.031), which remained significant with the inclusion of homeostasis model assessment of insulin resistance (HOMA-IR) in the model. Conclusion: Among Chinese postmenopausal women, bone quality was worse in prediabetes despite comparable bone density. Serum FGF21 levels showed a significant independent correlation with TBS, suggesting the potential impact of FGF21 on the deterioration of the bone microarchitecture in prediabetes.

A clinical prediction score using age at diagnosis and saline infusion test parameters can predict aldosterone-producing adenoma from idiopathic adrenal hyperplasia

PURPOSE

Accurate subtyping of the primary aldosteronism into aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH) is important to direct for specific treatment modalities. The objective of the study was to compare the clinical and biochemical parameters of APA and IAH patients to derive a Clinical Prediction Score reliably predicting APA from IAH.

METHODS

This was a retrospective multi-centre study recruiting 38 APA patients and 42 IAH patients from four major hospitals in Hong Kong using database from Surgical Outcomes Monitoring and Improvement Programme and Clinical Data Analysis and Reporting System. Their clinical and biochemical parameters were evaluated.

RESULTS

Patients in APA group were younger than IAH group (mean age 48.6 ± 9.2 vs. 57.1 ± 7.3 years old, p < 0.001), had more suppressed renin before saline infusion in saline infusion test (SIT) (median 0.19 [IQR 0.15-0.37] vs. 0.39 [IQR 0.19-0.69] ng/mL/h, p = 0.01), and higher aldosterone level after saline infusion in SIT (median 674 [IQR 498-1000] vs. 327 [IQR 242-483] pmol/L, p < 0.001). A clinical prediction score using three parameters was devised, comprising age at diagnosis < 50 years, PRA before saline infusion in SIT ≤ 0.26 ng/mL/h, and aldosterone level after saline infusion in SIT ≥ 424 pmol/L. A score of 2 would predict APA with a sensitivity of 84.2% and specificity of 88.1%, and a score of 3 would predict APA with a sensitivity of 31.6% and specificity of 100%.

CONCLUSIONS

Clinical Prediction Score based on the combination of age at diagnosis, PRA, and aldosterone level in the saline infusion tests could reliably predict APA from IAH.

Serum Metabolome of Coffee Consumption and its Association With Bone Mineral Density: The Hong Kong Osteoporosis Study

BACKGROUND

Inconsistent associations between coffee consumption and bone mineral density (BMD) have been observed in epidemiological studies. Moreover, the relationship of bioactive components in coffee with BMD has not been studied. The aim of the current study is to identify coffee-associated metabolites and evaluate their association with BMD.

METHODS

Two independent cohorts totaling 564 healthy community-dwelling adults from the Hong Kong Osteoporosis Study (HKOS) who visited in 2001-2010 (N = 329) and 2015-2016 (N = 235) were included. Coffee consumption was self-reported in an food frequency questionnaire. Untargeted metabolomic profiling on fasting serum samples was performed using liquid chromatography-mass spectrometry platforms. BMD at lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry. Multivariable linear regression and robust regression were used for the association analyses.

RESULTS

12 serum metabolites were positively correlated with coffee consumption after Bonferroni correction for multiple testing (P < 4.87 × 10-5), with quinate, 3-hydroxypyridine sulfate, and trigonelline (N'-methylnicotinate) showing the strongest association. Among these metabolites, 11 known metabolites were previously identified to be associated with coffee intake and 6 of them were related to caffeine metabolism. Habitual coffee intake was positively and significantly associated with BMD at the lumbar spine and femoral neck. The metabolite 5-acetylamino-6-formylamino-3-methyluracil (AFMU) (β = 0.012, SE = 0.005; P = 0.013) was significantly associated with BMD at the lumbar spine, whereas 3-hydroxyhippurate (β = 0.007, SE = 0.003, P = 0.027) and trigonelline (β = 0.007, SE = 0.004; P = 0.043) were significantly associated with BMD at the femoral neck.

CONCLUSIONS

12 metabolites were significantly associated with coffee intake, including 6 caffeine metabolites. Three of them (AFMU, 3-hydroxyhippurate, and trigonelline) were further associated with BMD. These metabolites could be potential biomarkers of coffee consumption and affect bone health.

Carbamylated Lipoproteins and Progression of Diabetic Kidney Disease

BACKGROUND AND OBJECTIVES

Protein carbamylation is a consequence of uremia and carbamylated lipoproteins contribute to atherogenesis in CKD. Proteins can also be carbamylated by a urea-independent mechanism, and whether carbamylated lipoproteins contribute to the progression of CKD has not been investigated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A case-control study was performed to determine whether there were changes in plasma levels of carbamylated lipoproteins in individuals with type 2 diabetes with eGFR >60 ml/min per 1.73 m² compared with a group of age- and sex-matched healthy controls. A cohort of 1320 patients with type 2 diabetes with baseline eGFR ≥30 ml/min per 1.73 m² was longitudinally followed up to evaluate the association between carbamylated lipoproteins and progression of CKD. The primary kidney outcome was defined as doubling of serum creatinine and/or initiation of KRT during follow-up. Plasma carbamylated LDLs and HDLs was measured by ELISA.

RESULTS

In individuals with diabetes with eGFR >60 ml/min per 1.73 m², both plasma carbamylated LDL and HDL levels were higher compared with healthy controls (P<0.001). After a mean follow-up of 9 years of the diabetic cohort, individuals in the top quartile of carbamylated LDL (hazard ratio, 2.21; 95% confidence interval, 1.42 to 3.46; P<0.001) and carbamylated HDL (hazard ratio, 4.53; 95% confidence interval, 2.87 to 7.13; P<0.001) had higher risk of deterioration of kidney function compared with those in the lowest quartile. On multivariable Cox regression analysis, plasma carbamylated LDL was no longer associated with kidney outcome after adjusting for baseline eGFR and potential confounding factors. However, the association between plasma carbamylated HDL and kidney outcome remained significant and was independent of HDL cholesterol.

CONCLUSIONS

Plasma carbamylated HDL but not carbamylated LDL was independently associated with progression of CKD in patients with type 2 diabetes.

Evaluation of GDF15 as a therapeutic target of cardiometabolic diseases in human: A Mendelian randomization study

Background

Growth differentiation factor 15 (GDF15) is a key regulator of body weight in animals by regulating food intake. Its receptor, glial cell-derived neurotrophic factor receptor alpha-like (GFRAL), was identified recently. Pre-clinical studies showed that it is a promising therapeutic target for cardiometabolic diseases and anorexia/cachexia. Although many pharmaceutical companies are developing drugs targeting GFRAL, whether the findings from animal studies can be extrapolated to man is unknown. Mendelian randomization (MR) is useful in investigating the relationship between risk factors and disease outcomes. We aimed to use a two-sample MR approach to evaluate the clinical usefulness of targeting GDF15 for cardiometabolic diseases.

Methods

Genetic instruments and summary statistics for MR analyses were obtained from a large genome-wide association study (GWAS) of GDF15 and cardiometabolic outcomes (n = 27,394 to 644,875), including body mass index, waist-hip ratio, waist circumference, whole-body lean mass, fat percentage, Type 2 Diabetes, fasting glucose, glycated haemoglobin, fasting insulin, LDL-cholesterol, HDL-cholesterol, total cholesterol, triglycerides, coronary artery disease, and estimated BMD (eBMD). Conventional inverse variance weighted (IVW) method was adopted to obtain the causal estimates of GDF-15 with different outcomes; weighted median and MR-egger were used for sensitivity analyses.

Findings

There was null association between GDF15 levels and anthropometric outcomes. One SD increase in genetically-determined GDF15 was significantly associated with reduced HDL-C (beta: -0.048SD; SE: 0.014; P = .001) but the result was not significant in sensitivity analyses. A consistent significant causal association was observed between GDF15 and eBMD in IVW (beta: 0.026 SD; SE: 0.005; P < .001) and subsequent sensitivity analyses.

Interpretation

This study sheds lights on the potential of drugs targeting the GDF15/GFRAL axis. It suggested that the effect of targeting GDF15/GFRAL axis for weight control in human may be different from the effects observed in animal studies. GDF15 treatment may improve BMD in humans.

Fund

No specific funding was received for this study.

Galectin-3 and risk of cardiovascular events and all-cause mortality in type 2 diabetes

AIMS

Recent clinical studies have shown that galectin-3 is a prognostic indicator in patients with coronary heart disease and in patients with heart failure. Experimental data suggest that galectin-3 may play a role in atherogenesis. We have evaluated whether serum galectin-3 level is associated with cardiovascular outcome in type 2 diabetes.

MATERIALS AND METHODS

Galectin-3 was measured in baseline samples in 1495 persons with type 2 diabetes. The primary cardiovascular outcome, incident cardiovascular events, was defined as first non-fatal myocardial infarction, non-fatal stroke, coronary revascularization, or death from cardiovascular cause. The secondary outcome was all-cause mortality.

RESULTS

At baseline, 12% of the subjects had prevalent cardiovascular disease. Serum galectin-3 was increased in the group with incident cardiovascular events compared with those who remained free of events during follow up (9.03 ± 2.98 ng/mL vs 8.15 ± 2.76, P < 0.01). Serum galectin-3 was also significantly increased in those subjects with a fatal outcome. The hazard ratios (HR) for cardiovascular events and all-cause mortality for individuals in the top quartile were 2.50 (95% CI 1.87, 3.36, P < 0.001) and 3.92 (95%CI 2.55, 6.01, P < 0.001), respectively. In a multivariate Cox regression analysis including traditional risk factors, log (eGFR), baseline albuminuria, and cardiovascular disease status, the HR per standard deviation change in galectin-3 was 1.13 (95% CI 1.02, 1.26, P = 0.02) for cardiovascular events and 1.17 (95% CI 1.01, 1.35, P = 0.04) for all-cause mortality.

CONCLUSIONS

Serum galectin-3 is associated with adverse cardiovascular outcomes in persons with type 2 diabetes independent of traditional risk factors.

A young Chinese man with nephrotic syndrome due to lipoprotein glomerulopathy

Lipoprotein glomerulopathy (LPG) is a rare autosomal dominant renal disease with incomplete penetrance, associated with specific protein-modifying mutations in the APOE gene. LPG is associated with poor renal prognosis, in which lipoprotein thrombi are seen in the glomerular capillaries. Dyslipidemia in LPG generally resembles type III hyperlipoproteinemia with elevated serum apolipoprotein E level. Fibrate is the most frequently reported lipid-lowering therapy in LPG as hypertriglyceridemia is common in these individuals. There are few existing case reports on effectiveness of statin monotherapy for LPG. We report a 32-year-old Chinese man who presented with nephrotic syndrome, renal impairment, severe hypercholesterolemia without hypertriglyceridemia, and hypertension. Renal biopsy confirmed lipoprotein glomerulopathy. Genetic testing confirmed APOE Kyoto mutation. Anti-hypertensive therapy, including angiotensin receptor blocker, and statin were initiated. Concomitant with normalization of lipid profile, his proteinuria markedly improved, and his renal function has remained stable up to 3 years, demonstrating sustained benefit with statin monotherapy in LPG.

Genetic Regulation of Pigment Epithelium-Derived Factor (PEDF): An Exome-Chip Association Analysis in Chinese Subjects With Type 2 Diabetes

Elevated circulating levels of pigment epithelium-derived factor (PEDF) have been reported in patients with type 2 diabetes (T2D) and its associated microvascular complications. This study aimed to 1) identify the genetic determinants influencing circulating PEDF levels in a clinical setting of T2D, 2) examine the relationship between circulating PEDF and diabetes complications, and 3) explore the causal relationship between PEDF and diabetes complications. An exome-chip association study on circulating PEDF levels was conducted in 5,385 Chinese subjects with T2D. A meta-analysis of the association results of the discovery stage (n = 2,936) and replication stage (n = 2,449) was performed. The strongest association was detected at SERPINF1 (p.Met72Thr; P_combined = 2.06 × 10^-57; β [SE] -0.33 [0.02]). Two missense variants of SMYD4 (p.Arg131Ile; P_combined = 7.56 × 10^-25; β [SE] 0.21 [0.02]) and SERPINF2 (p.Arg33Trp; P_combined = 8.22 × 10^-10; β [SE] -0.15 [0.02]) showed novel associations at genome-wide significance. Elevated circulating PEDF levels were associated with increased risks of diabetic nephropathy and sight-threatening diabetic retinopathy. Mendelian randomization analysis showed suggestive evidence of a protective role of PEDF on sight-threatening diabetic retinopathy (P = 0.085). Our study provided new insights into the genetic regulation of PEDF and further support for its potential application as a biomarker for diabetic nephropathy and sight-threatening diabetic retinopathy. Further studies to explore the causal relationship of PEDF with diabetes complications are warranted.

Serum follicle stimulating hormone is associated with reduced risk of diabetes in postmenopausal women: The Hong Kong osteoporosis study

Menopause is an important transition of reproductive stage in a woman's life. It is associated with diabetes, but the role of follicle stimulating hormone (FSH), a menopause-related hormone, in the risk of diabetes is largely unknown. We evaluated the relationship between serum FSH and diabetes in 1274 participants from the Hong Kong Osteoporosis Study aged≥55 at baseline. We also searched relevant databases for studies on serum FSH and incident diabetes and conducted a meta-analysis using fixed-effect modeling. Cases of incident diabetes (N = 60) were ascertained during a median follow-up of 10.7 years. Serum FSH was significantly associated with reduced risk of diabetes in both a crude model (hazard ratio [HR] per SD increase: 0.66; 95% CI: 0.48-0.89; P = 0.007) and a full model with adjustment for age, sex, body mass index, factors related to risk of diabetes, and reproductive health (HR per SD increase: 0.70; 95% CI: 0.51-0.97; P = 0.030); a similar result was observed when FSH was analysed in quintiles. In a fixed-effect meta-analysis of two studies, including the current study, serum FSH > 50 IU/L was associated with reduced risk of diabetes (HR = 0.56; 95% CI: 0.36-0.85; P = 0.006; I² = 0). In conclusion, serum FSH levels were independently associated with diabetes.

Galectin-3 is independently associated with progression of nephropathy in type 2 diabetes mellitus

AIMS/HYPOTHESIS

Galectin-3 has been implicated in cardiac and renal fibrosis and serves as a prognostic clinical indicator in heart failure. The aim of the present study was to evaluate whether serum galectin-3 level is associated with progressive kidney disease in type 2 diabetes.

METHODS

Galectin-3 was measured in baseline samples by ELISA in 1320 participants with type 2 diabetes with eGFR ≥30 ml min^-1 1.73 m^-2. The primary outcome was defined as doubling of serum creatinine and/or initiation of renal replacement therapy during follow-up. The secondary outcome was progression to macroalbuminuria in individuals with normo- or microalbuminuria at baseline.

RESULTS

Serum galectin-3 levels were significantly increased in a random subgroup of 270 type 2 diabetic individuals with eGFR >60 ml min^-1 1.73 m^-2 compared with an age- and sex-matched non-diabetic control group (7.58 ± 2.29 ng/ml vs 6.10 ± 1.91 ng/ml, respectively, p < 0.01). In the whole diabetic cohort, after a mean follow-up of 9 years, galectin-3 was independently associated with doubling of serum creatinine (HR 1.19; 95% CI 1.14, 1.24, p < 0.001) and incident macroalbuminuria (HR 1.20; 95% CI 1.12, 1.30, p < 0.001), even after adjusting for traditional risk factors, baseline eGFR and albuminuria status. Individuals with galectin-3 levels in the highest quartile had a fourfold risk of renal function loss and threefold risk of incident macroalbuminuria.

CONCLUSIONS/INTERPRETATION

Serum galectin-3 was independently associated with progressive renal disease in type 2 diabetes. Further mechanistic studies are warranted to determine whether galectin-3 is simply a disease biomarker or is also a mediator of the development and progression of diabetic nephropathy.

Serum 25-hydroxyvitamin D and the risk of stroke in Hong Kong Chinese

Low vitamin D levels have been associated with various cardiovascular diseases; however, whether it is associated with stroke remains inconclusive. We aimed to evaluate the association between serum 25-hydroxyvitamin D and risk of stroke. We conducted a cohort study consisting of 3,458 participants from the Hong Kong Osteoporosis Study aged ≥45 at baseline, examined between 1995 and 2010 and followed up using electronic medical records. Ischaemic and haemorrhagic stroke were defined using the ICD-9 code. In multivariable Cox-proportional hazard regression, quintiles 1 and 4 were significantly associated with increased risk of stroke when compared to the highest quintile (Quintile 1: HR, 1.78; 95 % CI, 1.16–2.74 and quintile 4: HR, 1.61; 95 % CI, 1.07–2.43). A similar association was observed in both men and women. In subgroup analysis, the association was specifically observed for ischaemic stroke, but not haemorrhagic stroke. Using a penalized regression spline, the association between vitamin D and risk of stroke was in a reverse J-shape, with the lowest risk of stroke being observed at 25(OH)D levels between 70 and 80 nmol/l. In conclusion, a low vitamin D level is associated with increased risk of ischaemic stroke; however, whether high vitamin D level is also associated with increased risk of stroke requires further study.

Supplementary Material to this article is available at www.thrombosis-online.com.

Annual direct medical costs associated with diabetes-related complications in the event year and in subsequent years in Hong Kong

AIM

To develop models to estimate the direct medical costs associated with diabetes-related complications in the event year and in subsequent years.

METHODS

The public direct medical costs associated with 13 diabetes-related complications were estimated among a cohort of 128 353 people with diabetes over 5 years. Private direct medical costs were estimated from a cross-sectional survey among 1825 people with diabetes. We used panel data regression with fixed effects to investigate the impact of each complication on direct medical costs in the event year and subsequent years, adjusting for age and co-existing complications.

RESULTS

The expected annual public direct medical cost for the baseline case was US$1,521 (95% CI 1,518 to 1,525) or a 65-year-old person with diabetes without complications. A new lower limb ulcer was associated with the biggest increase, with a multiplier of 9.38 (95% CI 8.49 to 10.37). New end-stage renal disease and stroke increased the annual medical cost by 5.23 (95% CI 4.70 to 5.82) and 5.94 (95% CI 5.79 to 6.10) times, respectively. History of acute myocardial infarction, congestive heart failure, stroke, end-stage renal disease and lower limb ulcer increased the cost by 2-3 times. The expected annual private direct medical cost of the baseline case was US$187 (95% CI 135 to 258) for a 65-year-old man without complications. Heart disease, stroke, sight-threatening diabetic retinopathy and end-stage renal disease increased the private medical costs by 1.5 to 2.5 times.

CONCLUSIONS

Wide variations in direct medical cost in event year and subsequent years across different major complications were observed. Input of these data would be essential for economic evaluations of diabetes management programmes.

An Exome-Chip Association Analysis in Chinese Subjects Reveals a Functional Missense Variant of GCKR That Regulates FGF21 Levels

Fibroblast growth factor 21 (FGF21) is increasingly recognized as an important metabolic regulator of glucose homeostasis. Here, we conducted an exome-chip association analysis by genotyping 5,169 Chinese individuals from a community-based cohort and two clinic-based cohorts. A custom Asian exome-chip was used to detect genetic determinants influencing circulating FGF21 levels. Single-variant association analysis interrogating 70,444 single nucleotide polymorphisms identified a novel locus, GCKR, significantly associated with circulating FGF21 levels at genome-wide significance. In the combined analysis, the common missense variant of GCKR, rs1260326 (p.Pro446Leu), showed an association with FGF21 levels after adjustment for age and sex (P = 1.61 × 10^-12; β [SE] = 0.14 [0.02]), which remained significant on further adjustment for BMI (P = 3.01 × 10^-14; β [SE] = 0.15 [0.02]). GCKR Leu446 may influence FGF21 expression via its ability to increase glucokinase (GCK) activity. This can lead to enhanced FGF21 expression via elevated fatty acid synthesis, consequent to the inhibition of carnitine/palmitoyl-transferase by malonyl-CoA, and via increased glucose-6-phosphate-mediated activation of the carbohydrate response element binding protein, known to regulate FGF21 gene expression. Our findings shed new light on the genetic regulation of FGF21 levels. Further investigations to dissect the relationship between GCKR and FGF21, with respect to the risk of metabolic diseases, are warranted.

Exome-chip association analysis reveals an Asian-specific missense variant in PAX4 associated with type 2 diabetes in Chinese individuals

AIMS/HYPOTHESIS

Genome-wide association studies (GWASs) have identified many common type 2 diabetes-associated variants, mostly at the intronic or intergenic regions. Recent advancements of exome-array genotyping platforms have opened up a novel means for detecting the associations of low-frequency or rare coding variants with type 2 diabetes. We conducted an exomechip association analysis to identify additional type 2 diabetes susceptibility variants in the Chinese population.

METHODS

An exome-chip association study was conducted by genotyping 5640 Chinese individuals from Hong Kong, using a custom designed exome array, the Asian Exomechip. Single variant association analysis was conducted on 77,468 single nucleotide polymorphisms (SNPs). Fifteen SNPs were subsequently genotyped for replication analysis in an independent Chinese cohort comprising 12,362 individuals from Guangzhou. A combined analysis involving 7189 cases and 10,813 controls was performed.

RESULTS

In the discovery stage, an Asian-specific coding variant rs2233580 (p.Arg192His) in PAX4, and two variants at the known loci, CDKN2B-AS1 and KCNQ1, were significantly associated with type 2 diabetes with exome-wide significance (p _discovery < 6.45 × 10^-7). The risk allele (T) of PAX4 rs2233580 was associated with a younger age at diabetes diagnosis. This variant was replicated in an independent cohort and demonstrated a stronger association that reached genome-wide significance (p _{meta-analysis} [p _meta] = 3.74 × 10^-15) in the combined analysis.

CONCLUSIONS/INTERPRETATION

We identified the association of a PAX4 Asian-specific missense variant rs2233580 with type 2 diabetes in an exome-chip association analysis, supporting the involvement of PAX4 in the pathogenesis of type 2 diabetes. Our findings suggest PAX4 is a possible effector gene of the 7q32 locus, previously identified from GWAS in Asians.

Practical considerations for the use of sodium-glucose co-transporter type 2 inhibitors in treating hyperglycemia in type 2 diabetes

Sodium-glucose co-transporter type 2 (SGLT2) inhibitors are a new class of oral anti-diabetic agents with a unique, insulin-independent mode of action. In patients with diabetes who have adequate renal function, SGLT2 inhibitors reduce hyperglycemia by blocking renal glucose reabsorption and increasing urinary glucose excretion. These agents are indicated for the treatment of hyperglycemia in type 2 diabetes mellitus (T2DM), as an adjunct to diet and exercise. In terms of efficacy, they are comparable to most other oral agents, and carry a low risk of hypoglycemia unless combined with sulfonylureas or insulin. They may be used in combination regimens with metformin, sulfonylureas, or insulin. Beyond glucose lowering, SGLT2 inhibitors are associated with modest weight loss and mild anti-hypertensive effects. Emerging cardiovascular and renal outcomes data suggest other potentially beneficial non-glycemic effects, although these findings await confirmation from further studies. The main adverse effects are increased risk of volume depletion and of genitourinary infections, although these can be managed with standard interventions. Rare cases of euglycemic ketoacidosis have been reported in a subset of patients treated with these agents, an issue currently under investigation. SGLT2 inhibitors represent a promising alternative treatment option for T2DM patients in whom the effectiveness of oral anti-hyperglycemic therapy is limited by the risk of hypoglycemia, weight gain, or other adverse effects. Safety and efficacy (up to 4 years) have been demonstrated in a range of T2DM patient populations, although more studies will be needed to determine whether treatment with SGLT2 inhibitors improves patient-important outcomes in the longer term.

Serum calcium and incident diabetes: an observational study and meta-analysis

The study aimed to prospectively evaluate if serum calcium is related to diabetes incidence in Hong Kong Chinese. The results showed that serum calcium has a significant association with increased risk of diabetes. The result of meta-analysis reinforced our findings.

INTRODUCTION

This study aimed to evaluate the association of serum calcium, including serum total calcium and albumin-corrected calcium, with incident diabetes in Hong Kong Chinese.

METHODS

We conducted a retrospective cohort study in 6096 participants aged 20 or above and free of diabetes at baseline. Serum calcium was measured at baseline. Incident diabetes was determined from several electronic databases. We also searched relevant databases for studies on serum calcium and incident diabetes and conducted a meta-analysis using fixed-effect modeling.

RESULTS

During 59,130.9 person-years of follow-up, 631 participants developed diabetes. Serum total calcium and albumin-corrected calcium were associated with incident diabetes in the unadjusted model. After adjusting for demographic and clinical variables, the association remained significant only for serum total calcium (hazard ratio (HR), 1.32 (95 % confidence interval (CI), 1.02-1.70), highest vs. lowest quartile). In a meta-analysis of four studies including the current study, both serum total calcium (pooled risk ratio (RR), 1.38 (95 % CI, 1.15-1.65); I (2) = 5 %, comparing extreme quantiles) and albumin-corrected calcium (pooled RR, 1.29 (95 % CI, 1.03-1.61); I (2) = 0 %, comparing extreme quantiles) were associated with incident diabetes. Penalized regression splines showed that the association of incident diabetes with serum total calcium and albumin-correlated calcium was non-linear and linear, respectively.

CONCLUSIONS

Elevated serum calcium concentration is associated with incident diabetes. The mechanism underlying this association warrants further investigation.

Exome-wide association analysis reveals novel coding sequence variants associated with lipid traits in Chinese

Blood lipids are important risk factors for coronary artery disease (CAD). Here we perform an exome-wide association study by genotyping 12,685 Chinese, using a custom Illumina HumanExome BeadChip, to identify additional loci influencing lipid levels. Single-variant association analysis on 65,671 single nucleotide polymorphisms reveals 19 loci associated with lipids at exome-wide significance (P<2.69 × 10⁻⁷), including three Asian-specific coding variants in known genes (CETP p.Asp459Gly, PCSK9 p.Arg93Cys and LDLR p.Arg257Trp). Furthermore, missense variants at two novel loci—PNPLA3 p.Ile148Met and PKD1L3 p.Thr429Ser—also influence levels of triglycerides and low-density lipoprotein cholesterol, respectively. Another novel gene, TEAD2, is found to be associated with high-density lipoprotein cholesterol through gene-based association analysis. Most of these newly identified coding variants show suggestive association (P<0.05) with CAD. These findings demonstrate that exome-wide genotyping on samples of non-European ancestry can identify additional population-specific possible causal variants, shedding light on novel lipid biology and CAD.

An important risk factor for coronary artery disease is the level of blood lipids. Here the authors conduct an exome-wide association study in Chinese cohorts and identify three novel loci associated with lipid levels as well as three Asian-specific variants in known loci.

Genetics of Apparently Sporadic Pheochromocytoma and Paraganglioma in a Chinese Population

Identification of germline mutation in patients with apparently sporadic pheochromocytomas and paragangliomas is crucial. Clinical indicators, which include young age, bilateral or multifocal, extra-adrenal, malignant, or recurrent tumors, predict the likelihood of harboring germline mutation in Caucasian subjects. However, data on the prevalence of germline mutation, as well as the applicability of these clinical indicators in Chinese, are lacking. We conducted a cross-sectional study at a single endocrine tertiary referral center in Hong Kong. Subjects with pheochromocytomas and paragangliomas were evaluated for the presence of germline mutations involving 10 susceptibility genes, which included NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, TMEM 127, MAX, and FH genes. Clinical indicators were assessed for their association with the presence of germline mutations. Germline mutations, 2 being novel, were found in 24.4% of the 41 Chinese subjects recruited and 11.4% among those with apparently sporadic presentation. The increasing number of the afore-mentioned clinical indicators significantly correlated with the likelihood of harboring germline mutation in one of the 10 susceptibility genes. (r=0.757, p=0.026). The presence of 2 or more clinical indicators should prompt genetic testing for germline mutations in Chinese subjects. In conclusion, our study confirmed that a significant proportion of Chinese subjects with apparently sporadic pheochromocytoma and paraganglioma harbored germline mutations and these clinical indicators identified from Caucasians series were also applicable in Chinese subjects. This information will be of clinical relevance in the design of appropriate genetic screening strategies in Chinese populations.

Serum Level of Soluble Receptor for Advanced Glycation End Products Is Associated with A Disintegrin And Metalloproteinase 10 in Type 1 Diabetes

BACKGROUND

The receptor for advanced glycation end products (RAGE) is involved in the pathogenesis of diabetic complications, and soluble forms of the receptor (sRAGE) can counteract the detrimental action of the full-length receptor by acting as decoy. Soluble RAGE is produced by alternative splicing [endogenous secretory RAGE (esRAGE)] and/or by proteolytic cleavage of the membrane-bound receptor. We have investigated the role of A Disintegrin And Metalloproteinase 10 (ADAM10) in the ectodomain shedding of RAGE.

METHODS

Constitutive and insulin-induced shedding of RAGE in THP-1 macrophages by ADAM10 was evaluated using an ADAM10-specific metalloproteinase inhibitor. Serum ADAM10 level was measured in type 1 diabetes and control subjects, and the association with serum soluble RAGE was determined. Serum total sRAGE and esRAGE were assayed by ELISA and the difference between total sRAGE and esRAGE gave an estimated measure of soluble RAGE formed by cleavage (cRAGE).

RESULTS

RAGE shedding (constitutive and insulin-induced) was significantly reduced after inhibition of ADAM10 in macrophages, and insulin stimulated ADAM10 expression and activity. Diabetic subjects have higher serum total sRAGE and esRAGE (p<0.01) than controls, and serum ADAM10 was also increased (p<0.01). Serum ADAM10 correlated with serum cRAGE in type 1 diabetes (r = 0.40, p<0.01) and in controls (r = 0.31. p<0.01) but no correlations were seen with esRAGE. The association remained significant after adjusting for age, gender, BMI, smoking status and HbA1c.

CONCLUSION

Our data suggested that ADAM10 contributed to the shedding of RAGE. Serum ADAM10 level was increased in type 1 diabetes and was a significant determinant of circulating cRAGE.

Cellular cholesterol transport proteins in diabetic nephropathy

Background

Lipid accumulation has been shown to accelerate renal injury, and the intracellular accumulation of lipids may be caused by alterations in synthesis as well as lipid uptake and efflux. We have investigated the role of cellular cholesterol transport proteins including adenosine triphosphate binding cassette transporter A1 (ABCA1), G1 (ABCG1) and scavenger receptor class B type I (SR-BI) in diabetic nephropathy.

Methods

Protein expression and the ability to mediate cholesterol efflux of ABCA1, ABCG1 and SR-BI was determined in human renal mesangial cells and proximal tubular epithelial cells cultured under normal or high glucose conditions. Renal expression of these cholesterol transporters was examined in a murine model of streptozotocin-induced type 1 diabetes.

Results

ABCA1, ABCG1 and SR-BI were expressed in both human renal mesangial cells and proximal tubular epithelial cells, and mediated cholesterol efflux to apolipoprotein AI and HDL. In vitro, hyperglycemia reduced the expression and the ability to mediate cholesterol efflux of all three cholesterol transporters (p<0.05). In vivo studies showed that intra-renal accumulation of lipids was increased in diabetic mice, particularly in mice with nephropathy. This was associated with a significant reduction in the expression of ABCA1, ABCG1 and SR-BI in the kidneys. These changes were already seen in diabetic mice without nephropathy and preceded the development of nephropathy. Diabetic mice with nephropathy had the lowest level of these cholesterol transporters.

Conclusion

Inducing diabetes with streptozotocin significantly reduced renal expression of ABCA1, ABCG1 and SR-BI. Defects in cholesterol export pathway in renal cells could therefore promote cholesterol accumulation and might contribute to the development of diabetic nephropathy.

A middle-aged man with increasing body fat

A 51-year-old man was referred for evaluation of gradual increase in body fat over bilateral arms, chest and abdomen for 6 months. He was a non-smoker and he drank at least four bottles of beer daily since the age of 18. There was no significant past medical history or any family history of obesity or endocrine diseases. Physical examination showed localized large bulk of fat over the neck, both arms and mammary regions, abdomen, and back (Figs  and ). The lower limbs and buttock were relatively spared. There was telangiectasia over the face and chest wall, but no palmar erythema nor finger clubbing. The liver span was normal, and the spleen tip was palpated 2 cm below the costal margin. Examination of the cardiovascular, respiratory and neurological system was normal. [Figure: see text] [Figure: see text] Blood tests showed thrombocytopenia (platelet 140 × 10(9)  L(-1) [normal: 170-380 × 10(9)  L(-1) ]) and liver function derangement (bilirubin 27 μmol L(-1) , ALP 298 U L(-1) , ALT 127 U L(-1) , AST 165 U L(-1) , GGT 1353 U L(-1) , albumin 33 g L(-1) and globulin 42 g L(-1) ). His clotting profile and renal functions were normal. His hepatitis B surface antigen was positive, but his HBV DNA was <60 copies per mL. Fasting glucose was 5.0 mmol L(-1) . HbA1c was 5.6%. His lipid profile was satisfactory with total cholesterol of 2.9 mmol L(-1) , triglycerides 1.0 mmol L(-1) , HDL-C 1.37 mmol L(-1) and LDL-C 1.1 mmol L(-1) . Ultrasound of the abdomen showed normal-sized liver with coarsened liver parenchymal echogenicity. The spleen was enlarged to 14 cm. This middle-aged man suffered from multiple symmetric lipomatosis and alcoholic liver disease. Dual-energy X-ray showed 1746 gm (40.1%), 1498 gm (32.8%) and 8322 gm (26.8%) fat over the left arm, right arm and trunk, respectively. The legs were unaffected with 1703 gm (19.4%) and 1627 gm (17.7%) fat over the left and right sides, respectively. The patient was advised to stop drinking and he declined surgical treatment.

Possible FRAX-based intervention thresholds for a cohort of Chinese postmenopausal women

SUMMARY

A total of 2,266 postmenopausal Chinese women were followed for 4.5 years to determine the incidence of new fractures. The positive predictive value, negative predictive value, sensitivity and specificity of different treatment strategies were compared. Using a fixed optimal threshold calculated from receiver operating characteristics (ROC) curve had the highest sensitivity but lowest specificity.

INTRODUCTION

There is no specific intervention threshold based on FRAX to guide treatment for Asian populations. This prospective study sought to determine the impact of applying different intervention thresholds to a cohort of Chinese postmenopausal women.

METHODS

This study was part of the Hong Kong Osteoporosis Study. A total of 2,266 treatment-naïve postmenopausal women underwent clinical risk factor and BMD assessments. The subjects were followed to assess fractures. We calculated the FRAX probability of major osteoporotic fractures corresponding to women with prior fractures but no other clinical risk factors. Different treatment strategies which include treating women with prior fractures, women with age-specific FRAX probability corresponding to those with prior fractures, women with osteoporosis as well as women with FRAX probability above a fixed cut-off based on optimizing sensitivity and specificity on the ROC curve were compared.

RESULTS

The mean age at baseline was 62.1 ± 8.5 years, and the mean follow-up time was 4.5 ± 2.8 years. One hundred six new major osteoporotic fractures were reported. An optimal (FRAX, with BMD) cut-off point of 9.95 % was identified. All strategies had negative predictive value of >90 %. Using a fixed cut-off had the highest sensitivity (62.3 %) but lowest specificity (73.5 %) and positive predictive value (10.3 %). Using a fixed cut-off would direct treatment from younger women with lower absolute risk to elderly women with higher absolute risk.

CONCLUSION

Targeting only women with prior fractures is unlikely to reduce fracture burden. Other treatment strategies with higher sensitivity need to be considered but they have different shortcomings.

Outcomes of applying the NOF, NOGG and Taiwanese guidelines to a cohort of Chinese early postmenopausal women

OBJECTIVE

We applied the NOF (National Osteoporosis Foundation, USA), NOGG (National Osteoporosis Guideline Group, UK) and Taiwanese guidelines to a cohort of postmenopausal women and compared the effectiveness in fracture prevention according to these guidelines.

DESIGN

This study is part of the Hong Kong Osteoporosis Study in which postmenopausal women underwent regular assessment and followed up for fracture outcome.

SUBJECTS

We studied 2266 treatment-naïve postmenopausal women with mean age of 62·1 years and mean follow-up of 4·5 years.

MEASUREMENT

The treatment recommendations based on different guidelines were compared. The women were followed up to determine the rate of fracture occurrence.

RESULTS

A total of 106 new major osteoporotic fractures (MOF) were reported, of which 21 were hip fractures (HF). Application of the NOF, NOGG and Taiwanese guidelines resulted in bone mineral density (BMD) screening of 40·7%, 1·3% and 31·8% and treatment of 26·8%, 15·5% and 25·4% of the cohort, respectively. 85·7%, 52·4% and 85·7% of the subjects who sustained HFs would be offered treatment according to the NOF, NOGG and Taiwanese guidelines, respectively. Likewise, 58·5%, 34% and 59·4% of the subjects who sustained MOF would be offered treatment according to the 3 guidelines, respectively. The clinical utility indexes for the 3 guidelines based on the occurrence of MOF during follow-up were 0·0597, 0·0345 and 0·0651, respectively. The corresponding numbers for HFs were even lower.

CONCLUSION

The clinical utility for these three guidelines is low for this postmenopausal cohort. Specific guidelines should be needed to guide BMD screening and treatment in our society.

Genetic analysis of recently identified osteoporosis susceptibility genes in southern Chinese

CONTEXT

Fifty-six genomic loci recently were identified as associated with bone mineral density (BMD) in a large meta-analysis study of mainly European-descent subjects. Circulating factors related to calcium and phosphate metabolism, eg, serum levels of calcium, phosphate, vitamin D metabolites, PTH, and alkaline phosphatase (ALP), may affect bone turnover and metabolism.

OBJECTIVE AND DESIGN

We aimed to investigate the effects of these reported variants, as well as their interactions with 5 studied circulating factors, on BMD in a southern Chinese prospective cohort (n = 2670). The identified interactions were further replicated in an independent cohort of 800 Chinese females.

RESULTS

Approximately half (n = 27) of the reported variants were successfully replicated in our sample of southern Chinese individuals. We further demonstrated a significant interaction between MARK3 and serum ALP levels (Pmeta = 9.89 ×10(-6)); the effect of MARK3 rs11623869 on BMD was stronger in the presence of high serum levels of ALP. In addition, several interactions between other genes and circulating factors were suggested.

CONCLUSIONS

Our study has provided an independent replication of associations between several reported loci and BMD in a large sample of southern Chinese individuals. These replicated loci may represent osteoporosis susceptibility genes in both Chinese and European-descent populations. Furthermore, we have shown that serum ALP levels modified the association of MARK3 with BMD. Understanding the mechanisms of the interactions between BMD-related loci and circulating factors may help to determine the pathogenesis of susceptibility to osteoporosis and could have implications for clinical care.

Impact of serum amyloid A on cellular cholesterol efflux to serum in type 2 diabetes mellitus

OBJECTIVE

Serum amyloid A (SAA) is an acute phase response protein and has apolipoprotein properties. Since type 2 diabetes is associated with chronic subclinical inflammation, the objective of this study is to investigate the changes in SAA level in type 2 diabetic patients and to evaluate the relationship between SAA and the capacity of serum to induce cellular cholesterol efflux via the two known cholesterol transporters, scavenger receptor class B type I (SR-BI) and ATP-binding cassette transporter G1 (ABCG1).

METHODS

264 patients with type 2 diabetes mellitus (42% with normoalbuminuria, 30% microalbuminuria, and 28% proteinuria) and 275 non-diabetic controls were recruited. SAA was measured by ELISA. SR-BI and ABCG1-mediated cholesterol efflux to serum were determined by measuring the transfer of [(3)H]cholesterol from Fu5AH rat hepatoma cells expressing SR-BI and from human ABCG1-transfected CHO-K1 cells to the medium containing the tested serum respectively.

RESULTS

SAA was significantly increased in diabetic patients with incipient or overt nephropathy. Both SR-BI and ABCG1-mediated cholesterol efflux to serum were significantly impaired in all three groups of diabetic patients (p < 0.01). SAA inversely correlated with SR-BI-mediated cholesterol efflux (r = -0.36, p < 0.01) but did not correlate with ABCG1-mediated cholesterol efflux. Stepwise linear regression analysis showed that HDL, the presence or absence of diabetes, and log(SAA) were significant independent determinants of SR-BI-mediated cholesterol efflux to serum.

CONCLUSION

SAA was increased in type 2 diabetic patients with incipient or overt nephropathy, and SAA was associated with impairment of SR-BI-mediated cholesterol efflux to serum.

Genetic variants in GREM2 are associated with bone mineral density in a southern Chinese population

CONTEXT

Gremlin 2 (GREM2) is a regulator of osteoblast differentiation and osteogenesis. A recent genome-wide association study identified GREM2 as a novel susceptibility gene for trabecular volumetric bone mineral density (BMD).

OBJECTIVE

We investigated whether GREM2 gene variants were associated with areal BMD in southern Chinese people.

RESEARCH DESIGN AND METHODS

We genotyped 108 single-nucleotide polymorphisms (SNPs) in 417 cases (defined as BMD Z-score ≤-1.28) and 359 controls (defined as BMD Z-score ≥+1). Multivariable logistic regression using an additive model was used to evaluate the association. The most associated SNPs of BMD at the spine, femoral neck, and total hip was then replicated in an additional 454 cases and 401 controls.

RESULTS

Twelve, 13, and 14 SNPs showed nominal association with BMD at the spine, femoral neck, and total hip, respectively. The minor alleles of rs9728351 (odds ratio [OR] = 2.56; 95% confidence interval [CI] = 1.33-4.92), rs11588607 (OR = 1.65; 95% CI = 1.14-2.4), and rs4454537 (OR = 1.87; 95% CI = 1.22-2.86) were associated with the low BMD at the spine, femoral neck, and total hip, respectively. Among these SNPs most associated with BMD, rs4454537 was successfully replicated in an independent cohort (OR = 1.59; 95% CI = 1.05-2.4). Meta-analysis showed that the minor allele of rs4454537 was associated with low total hip BMD with an OR of 1.72 (95% CI = 1.28-2.31) (P = 3.2 × 10(-4); P(corrected) = .043).

CONCLUSIONS

The minor allele of rs4454537 is significantly associated with low BMD at the total hip of southern Chinese people. Our study further suggests GREM2 as a novel susceptibility gene for osteoporosis.