Evaluating risk factors associated with severe hypoglycaemia in epidemiology studies-what method should we use?

Evaluating the Incidence and Risk Factors Associated With Mild and Severe Hypoglycemia in Insulin-Treated Type 2 Diabetes

OBJECTIVES

This study to assess the incidence rates and risk factors of hypoglycemia in a wide real-life sample of patients with insulin-treated type 2 diabetes mellitus.

METHODS

In a prospective epidemiological study, data from 817 subjects were collected from medical records and via interviews. Over a 3-month period, hypoglycemic episodes were recorded via self-measurement of glucose levels at least twice daily. Cox proportional and negative binomial multivariable models were applied to estimate adjusted and unadjusted hazard ratios and incidence rate ratios of hypoglycemic events.

RESULTS

Of the 817 patients, 52.9% experienced hypoglycemia, 38.1% had only nonsevere episodes, and 14.8% had at least 1 severe episode. Total events per patient-year were estimated at 13.3 (±24.8), with 11.8 (±21.6) and 1.4 (±4.7) being nonsevere and severe, respectively. History of hypoglycemia and severe hypoglycemia were consistent risk factors of hypoglycemia. Intensification of therapy was associated with higher incidence rates, whereas the effect on the hazard rates was more moderate. Longer duration of insulin therapy and the presence of congestive heart failure were associated with a higher risk of developing and frequency of hypoglycemia. Hypoglycemia awareness was found to independently affect only mild hypoglycemia.

CONCLUSIONS

Hypoglycemia is a common complication in patients with insulin-treated type 2 diabetes mellitus. The risk factors of developing hypoglycemia are to some extent different from those of the frequency of hypoglycemic episodes. Particular attention is required for patients with recurrent hypoglycemic events and on intensive antidiabetic therapy.

Emergency attendance for acute hyper- and hypoglycaemia in the adult diabetic population of the metropolitan area of Milan: quantifying the phenomenon and studying its predictors

BACKGROUND

We quantified, among diabetic adults, the frequency, costs, and factors associated with visits to the emergency department (EDs) and subsequent hospitalizations for acute hypoglycaemic and hyperglycaemic events.

METHODS

We included adults with diabetes residing in the Milan Agency for Health Protection between 2015 and 2017. From healthcare databases, we identified demographic variables, comorbidities, type of treatment, insulin treatment duration, previous ED attendances for acute glycaemic events, and two indicators of glycaemic monitoring. Using a validated ICD-9-CM coding algorithm, we identified all ED attendances for acute glycaemic events from the ED database and calculated their incidence. We computed the direct costs from health databases and presented them as average annual mean costs for those having had at least an ED attendance. The analysis of the association between the number of ED attendances and potential determinants was performed using zero-inflated negative binomial regression models. These two-part models concomitantly estimate two sets of parameters: the odds-ratios (ORs) of having no attendances and the incidence rate ratios (IRRs) of attendance.

RESULTS

The cohort included 168,285 subjects, 70% of subjects were older than 64 years, 56% were males, and 26% were treated with insulin. The incidence of acute glycaemic events for those attending the ED was 7.0 per 1000 patient-years, followed by hospitalization 26.0% of the time. The total annual direct cost for ED attendances due to acute glycaemic events was 174,000 €. Type of antidiabetic treatment had the strongest association with ED attendances for hypoglycaemia. Patients assuming insulin only had a lower probability of having no attendances (OR compared to those who assumed non-insulin antidiabetic drugs =0.01, 95% CI = 0.00-0.02). These patients also had the highest rate of hyperglycaemic episodes (IRR = 7.7, 95% CI = 5.1-11.7 for insulin only vs. non-insulin antidiabetic drugs). Subjects having had a previous episode of the same type leading to an ED visit had a higher rate of subsequent attendances (IRR for hypoglycaemia = 5.3, 95% CI = 3.9-7.3 and IRR for hyperglycaemia = 3.7, 95% CI = 1.3-10.2).

CONCLUSION

Insulin treatment and having had a prior acute glycaemic event leading to an ED visit were major predictors of ED attendance for hyper and hypoglycaemia in a population of adults with diabetes.

Modeling marginal features in studies of recurrent events in the presence of a terminal event

We study models for recurrent events with special emphasis on the situation where a terminal event acts as a competing risk for the recurrent events process and where there may be gaps between periods during which subjects are at risk for the recurrent event. We focus on marginal analysis of the expected number of events and show that an Aalen-Johansen type estimator proposed by Cook and Lawless is applicable in this situation. A motivating example deals with psychiatric hospital admissions where we supplement with analyses of the marginal distribution of time to the competing event and the marginal distribution of the time spent in hospital. Pseudo-observations are used for the latter purpose.

Decreasing Trends in Mean HbA1c Are Not Associated With Increasing Rates of Severe Hypoglycemia in Children: A Longitudinal Analysis of Two Contemporary Population-Based Pediatric Type 1 Diabetes Registries From Australia and Germany/Austria Between 1995 and 2016

OBJECTIVE

To investigate temporal trends in glycemic control and severe hypoglycemia rates for pediatric patients with type 1 diabetes from 1995 to 2016 by analyzing data from the longitudinal, prospective, population-based German/Austrian (Diabetes Patient History Documentation [DPV]) and Western Australian (Western Australian Children's Diabetes Database [WACDD]) diabetes registries.

RESEARCH DESIGN AND METHODS

Patients diagnosed with type 1 diabetes aged <15 years were identified from the DPV (N = 59,883) and WACDD (N = 2,595) registries and data extracted for all clinic visits occurring between 1995 and 2016, inclusive. Mean HbA_1c and severe hypoglycemia (self-reported loss of consciousness/convulsion) rates were calculated per 100 patient-years.

RESULTS

Between 1995 and 2016, the annual mean HbA_1c decreased from 8.3 to 7.8% in the DPV cohort and from 9.2 to 8.3% in the WACDD cohort. Over the same period, the severe hypoglycemia rate decreased by an annual average of 2% (relative risk 0.983 [95% CI 0.981, 0.986]) in the DPV cohort and 6% (relative risk 0.935 [95% CI 0.934, 0.937]) in the WACDD cohort. Concomitant decreasing trends in both HbA_1c and severe hypoglycemia rates were observed in boys and girls, all age-groups, and injection therapy/pump regimen groups.

CONCLUSIONS

Over the past two decades, there have been concurrent improvements in HbA_1c and decreasing severe hypoglycemia rates in two contemporary, longitudinal, population-based pediatric cohorts of type 1 diabetes. Translation of these data into clinical practice and patient education may reduce fear of hypoglycemia and enable better glycemic control.

Temporal changes in the incidence and predictors of severe hypoglycaemia in type 2 diabetes: The Fremantle Diabetes Study

AIM

To determine the incidence of severe hypoglycaemia and its predictors in community-based patients with type 2 diabetes studied between 2008 and 2013 compared with those in a cohort of patients with type 2 diabetes from the same geographical area assessed a decade earlier.

METHODS

We studied 1551 participants (mean age 65.7 years, 51.9% men) with type 2 diabetes from the longitudinal observational Fremantle Diabetes Study Phase II (FDS2). Severe hypoglycaemia was ascertained as that requiring ambulance attendance, emergency department services and/or hospitalization. Cox proportional hazards modelling was used to determine predictors of a first episode of severe hypoglycaemia, and negative binomial regression was used to identify predictors of frequency.

RESULTS

Sixty-three participants (4.1%) experienced 83 episodes, representing an incidence of 1.34/100 participant-years (95% confidence interval [CI] 1.08 to 1.67; vs 1.67/100 participant-years [95% CI 1.31-2.13] in the Fremantle Diabetes Study Phase I [FDS1]; P = 0.18). Those experiencing severe hypoglycaemia experienced one to four episodes in both cohorts. The independent predictors of incident severe hypoglycaemia in the FDS2 were: older age; higher educational attainment; alcohol consumption; current smoking; sulphonylurea/insulin treatment; prior severe hypoglycaemia; renal impairment; and plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP). The same variables except smoking were associated with frequency of severe hypoglycaemia. Most of these risk factors paralleled those in the FDS1, but current smoking and plasma NT-proBNP were novel.

CONCLUSIONS

The incidence and frequency of severe hypoglycaemia did not change between the Fremantle Diabetes Study phases but novel risk factors, including plasma NT-proBNP, were observed in the FDS2.

Effect of Insulin Analogs on Frequency of Non-Severe Hypoglycemia in Patients with Type 1 Diabetes Prone to Severe Hypoglycemia: Much Higher Rates Detected by Continuous Glucose Monitoring than by Self-Monitoring of Blood Glucose-The HypoAna Trial

BACKGROUND

Hypoglycemia is an increasingly important endpoint in clinical diabetes trials. The assessment of hypoglycemia should therefore be as complete as possible. Blinded continuous glucose monitoring (CGM) provides an improved opportunity to capture asymptomatic and nocturnal events. Here we report results from the HypoAna trial comparing all-analog-insulin therapy (aspart/detemir) with all-human-insulin therapy (neutral protamine Hagedorn/regular) on non-severe hypoglycemia (symptomatic and asymptomatic hypoglycemia) as assessed by blinded CGM and compared with data obtained by self-monitoring of blood glucose (SMBG) in patients with type 1 diabetes and recurrent severe hypoglycemia.

METHODS

Fifty-three patients completed a substudy of 4 × 3 days of blinded CGM. CGM traces were reviewed for hypoglycemic events lasting 15 min or longer.

RESULTS

At the threshold ≤3.9 mmol/L, the per-protocol analysis demonstrated a 40% rate reduction (95% confidence interval [CI] 20%-60%; P = 0.002) in nocturnal non-severe hypoglycemia during analog treatment, mainly due to a 40% rate reduction (95% CI 0%-70%; P = 0.03) of nocturnal asymptomatic hypoglycemia. Similar nonsignificant trends were seen at the glucose threshold ≤3.0 mmol/L. Overall CGM-detected that nocturnal asymptomatic hypoglycemia ≤3.9 mmol/L was ∼17 times more frequent than SMBG-detected episodes (52 vs. 3 events/patient-year). This translates into a time needed to treat one patient with insulin analogs to prevent one episode that is 34 times shorter using CGM data than SMBG data (1.4 vs. 47 weeks).

CONCLUSIONS

Capturing hypoglycemic events by the conventional method of SMBG in patients with impaired awareness reveals only a limited number of events. Blinded CGM can provide more complete data, particularly in terms of asymptomatic and nocturnal events.

Severe hypoglycemia rates are not associated with HbA1c: a cross-sectional analysis of 3 contemporary pediatric diabetes registry databases

OBJECTIVE

To examine the association between glycated hemoglobin (HbA1c) and severe hypoglycemia rates in patients with type 1 diabetes receiving usual care, by analysing data from the US Type 1 Diabetes Exchange (T1DX), German/Austrian Diabetes Patienten Verlaufsdokumenation (DPV), and Western Australian Children Diabetes Database (WACDD) diabetes registries.

METHODS

Data for patients with type 1 diabetes, aged <18 years with a minimum duration of diabetes of 2 years, were extracted from each registry for a 12-month observation period between 2011 and 2012 (7,102 T1DX, 18,887 DPV, and 865 WACDD). Rates of severe hypoglycemia (self-reported loss of consciousness/convulsion) were estimated per 100 patient-years and analyzed by HbA1c, source registry, treatment regimen, and age group.

RESULTS

Overall, the severe hypoglycemia rate per 100 patient years was 7.1, 3.3, and 6.7 in T1DX, DPV, and WACDD patients, respectively. Lower HbA1c was not associated with an increased rate of severe hypoglycemia when examined by source registry, treatment regimen, or age group.

CONCLUSION

An inverse relationship between mean HbA1c and risk of severe hypoglycemia was not observed in this study of 3, independent cohorts of children and adolescents with type 1 diabetes. Investigation in other large, longitudinal cohorts is recommended to further characterize the contemporary relationship between glycemic control and risk of severe hypoglycemia rates in pediatric patients with type 1 diabetes.

Reporting Severe Hypoglycemia in Type 1 Diabetes: Facts and Pitfalls

PURPOSE OF REVIEW

To describe potential factors influencing reporting of severe hypoglycemia in adult patients with type 1 diabetes and to analyze their effect on reported rates of severe hypoglycemia.

RECENT FINDINGS

Reported rates of severe hypoglycemia defined as need for third party assistance vary between 0.3-3.0 events per patient-year in unselected cohorts, corresponding to a yearly prevalence range of 10-53%. When defined as need for parenteral therapy with glucose or glucagon or need for admission to an emergency unit or hospitalization, incidence and prevalence rates of severe hypoglycemia are 0.02-0.5 events per patient-year and 1-29%, respectively. When subjects with recurrent severe hypoglycemia in the past or suffering from impaired hypoglycemia awareness are excluded from participation in studies, lower rates are reported. Studies applying anonymous reporting or reporting by partners report higher rates of severe hypoglycemia. There is a large variation between studies reporting incidence and prevalence of severe hypoglycemia in patients with type 1 diabetes, mainly explained by definition of severity, methods of reporting, and patient selection. These findings call for consensus about hypoglycemia definition and reporting in future research.

Incidence of severe hypoglycemia in children with type 1 diabetes in the Nordic countries in the period 2008-2012: association with hemoglobin A 1c and treatment modality

OBJECTIVE

Treatment of type 1 diabetes has been intensified aiming at normalizing blood glucose, which may increase the risk of severe hypoglycemia (SH). We aimed to compare the incidence of SH events in the four Nordic countries Denmark, Iceland, Norway and Sweden, and to assess the influence of hemoglobin A1c (HbA_1c) and treatment modalities on the frequency of SH; particularly, to explore if a HbA_1c target ≤6.7% (50 mmol/mol) is feasible.

RESEARCH DESIGN AND METHODS

Data on children below 15 years with a diabetes duration more than 1 year, registered in the national childhood diabetes databases in the four Nordic countries from 2008 to 2012, were compiled. Data completeness was more than 95%.

RESULTS

Totally 8806 (48% females) patients with 29 715 person years were included, mean age and diabetes duration were 11 years and 5.1 years, respectively. The overall rate of SH was 6.0 per 100 patient-years, and did not change during the study period. The Swedish population constantly had the lowest SH incidence while it decreased significantly in the Danish population. HbA_1c decreased significantly over time (p<0.01), while the number of pump users increased (p<0.01). Stratifying for HbA_1c levels showed the lowest risk of SH in patients with HbA_1c ≤6.7% (≤50 mmol/mol), but in the statistical models adjusting for possible confounders the difference between the HbA_1c groups disappeared. Pump users had the lowest SH risk, also after adjusting for possible confounders.

CONCLUSIONS

Risk of SH differs between the Nordic countries with the lowest risk in Sweden. Pump therapy was associated with decreased risk of SH. The low HbA_1c group had the same or a lower risk of SH compared with the highest HbA_1c groups. A target HbA_1c ≤6.7% (≤50 mmol/mol) seems achievable without increasing the risk of SH.

Increasing trend in emergency department visits for hypoglycemia from patients with type 2 diabetes mellitus in Taiwan

AIMS

We analyze the time trends of hypoglycemia-related emergency department visits in Taiwan between 2000 and 2010, focusing on type 2 diabetic patients receiving antidiabetic agents.

METHODS

From a national dataset containing longitudinal medical claims of one million persons, we ascertained 4479 hypoglycemia-related emergency department visits from 3184 type 2 diabetic patients for analysis. We used negative binomial regression to calculate the incidence rate ratios (IRRs) for comparing event rates of hypoglycemia-related emergency department visits in different study periods.

RESULTS

Rates of hypoglycemia-related emergency department visits increased 4.8 folds from year 2000 to 2010 (adjusted IRR 4.88, 95% CI 3.94-6.05, P<0.001). Severe hypoglycemia requiring emergency department visits prevailed among women, older patients (≥ 65 years), and those not lived in the urban areas.

CONCLUSIONS

Within a 10-year period, there was a substantial increase in the rates of hypoglycemia-related emergency department visits from type 2 diabetic patients in Taiwan. Appropriate risk management plans should be developed to prevent the occurrence of severe hypoglycemia in patients with type 2 diabetes in Taiwan.

Urinary symptoms following external beam radiotherapy of the prostate: Dose-symptom correlates with multiple-event and event-count models

BACKGROUND AND PURPOSE

This study aimed to compare urinary dose-symptom correlates after external beam radiotherapy of the prostate using commonly utilised peak-symptom models to multiple-event and event-count models which account for repeated events.

MATERIALS AND METHODS

Urinary symptoms (dysuria, haematuria, incontinence and frequency) from 754 participants from TROG 03.04-RADAR trial were analysed. Relative (R1-R75 Gy) and absolute (A60-A75Gy) bladder dose-surface area receiving more than a threshold dose and equivalent uniform dose using exponent a (range: a ∈[1 … 100]) were derived. The dose-symptom correlates were analysed using; peak-symptom (logistic), multiple-event (generalised estimating equation) and event-count (negative binomial regression) models.

RESULTS

Stronger dose-symptom correlates were found for incontinence and frequency using multiple-event and/or event-count models. For dysuria and haematuria, similar or better relationships were found using peak-symptom models. Dysuria, haematuria and high grade (⩾ 2) incontinence were associated to high dose (R61-R71 Gy). Frequency and low grade (⩾ 1) incontinence were associated to low and intermediate dose-surface parameters (R13-R41Gy). Frequency showed a parallel behaviour (a=1) while dysuria, haematuria and incontinence showed a more serial behaviour (a=4 to a ⩾ 100). Relative dose-surface showed stronger dose-symptom associations.

CONCLUSIONS

For certain endpoints, the multiple-event and event-count models provide stronger correlates over peak-symptom models. Accounting for multiple events may be advantageous for a more complete understanding of urinary dose-symptom relationships.

Hypoglycaemia in diabetes mellitus: epidemiology and clinical implications

Hypoglycaemia is a frequent adverse effect of treatment of diabetes mellitus with insulin and sulphonylureas. Fear of hypoglycaemia alters self-management of diabetes mellitus and prevents optimal glycaemic control. Mild (self-treated) and severe (requiring help) hypoglycaemia episodes are more common in type 1 diabetes mellitus but people with insulin-treated type 2 diabetes mellitus are also exposed to frequent hypoglycaemic events, many of which occur during sleep. Hypoglycaemia can disrupt many everyday activities such as driving, work performance and leisure pursuits. In addition to accidents and physical injury, the morbidity of hypoglycaemia involves the cardiovascular and central nervous systems. Whereas coma and seizures are well-recognized neurological sequelae of hypoglycaemia, much interest is currently focused on the potential for hypoglycaemia to cause dangerous and life-threatening cardiac complications, such as arrhythmias and myocardial ischaemia, and whether recurrent severe hypoglycaemia can cause permanent cognitive impairment or promote cognitive decline and accelerate the onset of dementia in middle-aged and elderly people with diabetes mellitus. Prevention of hypoglycaemia is an important part of diabetes mellitus management and strategies include patient education, glucose monitoring, appropriate adjustment of diet and medications in relation to everyday circumstances including physical exercise, and the application of new technologies such as real-time continuous glucose monitoring, modified insulin pumps and the artificial pancreas.

AUTONOMY: the first randomized trial comparing two patient-driven approaches to initiate and titrate prandial insulin lispro in type 2 diabetes

OBJECTIVE

To compare two self-titration algorithms for initiating and escalating prandial insulin lispro in patients with type 2 diabetes inadequately controlled on basal insulin.

RESEARCH DESIGN AND METHODS

The trial was designed as two independent, multinational, parallel, open-label studies (A and B), identical in design, to provide substantial evidence of efficacy and safety in endocrine and generalist settings. Subjects were 18-85 years old (study A: N = 528; study B: N = 578), on basal insulin plus oral antidiabetic drugs for ≥3 months, and had an HbA1c 7.0% to ≤12.0% (>53.0 to ≤107.7 mmol/mol). Once optimized on insulin glargine, subjects were randomized to one of two self-titration algorithm groups adjusting lispro either every day (Q1D) or every 3 days (Q3D) for 24 weeks. The primary outcome was the change in HbA1c from baseline. The primary and secondary objectives were evaluated for the overall population and subjects ≥65 years old.

RESULTS

Baseline HbA1c was similar (study A: Q1D 8.3% [67.2 mmol/mol] vs. Q3D 8.4% [68.3 mmol/mol], P = 0.453; study B: Q1D 8.3% [67.2 mmol/mol] vs. Q3D 8.4% [68.3 mmol/mol], P = 0.162). Both algorithms had significant and equivalent reductions in HbA1c from baseline (study A: Q3D -0.96% [-10.49 mmol/mol], Q1D -1.00% [-10.93 mmol/mol], Q3D-Q1D 0.04% [0.44 mmol/mol] [95% CI -0.15 to 0.22 (-1.64 to 2.40)]; study B: Q3D -0.92% [-10.06 mmol/mol], Q1D -0.98% [-10.71 mmol/mol], Q3D-Q1D 0.06% [0.66 mmol/mol] [95% CI -0.12 to 0.24 (-1.31 to 2.62)]). The incidence and rate of hypoglycemia were similar for Q3D and Q1D in both studies. In general, no clinically relevant differences were found between the two algorithms in subjects ≥65 years old in either study.

CONCLUSIONS

Prandial insulin lispro can effectively and safely be initiated, by either of two self-titrated algorithms, in a variety of practice settings.

Effect of insulin analogues on risk of severe hypoglycaemia in patients with type 1 diabetes prone to recurrent severe hypoglycaemia (HypoAna trial): a prospective, randomised, open-label, blinded-endpoint crossover trial

BACKGROUND

Insulin analogues have been developed to reduce the risk of hypoglycaemia in patients with diabetes who require insulin-based treatment, but their effect on this endpoint in patients with type 1 diabetes complicated by recurrent severe hypoglycaemia is unknown. We compared the occurrence of severe hypoglycaemic episodes in such patients during treatment with insulin analogues or human insulin.

METHODS

In this investigator-initiated, prospective, randomised, open-label, blinded-endpoint crossover trial at seven medical centres in Denmark, we recruited patients (aged ≥18 years) with type 1 diabetes (diagnosed for >5 years) who had reported two or more episodes of severe hypoglycaemia in the preceding year. Patients were randomly assigned (1:1) using computer-generated site-specific randomisation lists in blocks of four to treatment with basal-bolus therapy with either analogue insulin (detemir and aspart) or human insulin (human neutral protamine Hagedorn and human regular) in a balanced crossover design. A 1-year plus 1-year treatment period was specified, consisting of two 3-month run-in periods, each followed by a 9-month maintenance period. The primary endpoint was the number of validated episodes of severe hypoglycaemia (defined by need for treatment assistance from others) reported during the maintenance periods, analysed by intention to treat. The study is registered with ClinicalTrials.gov, number NCT00346996.

FINDINGS

Between May 9, 2007, and Oct 30, 2009, 159 patients were randomly assigned. 18 patients discontinued during the first run-in period, leaving 141 patients in the intention-to-treat population. 136 severe hypoglycaemic episodes were reported during treatment with human insulin and 105 episodes were reported during treatment with insulin analogues, resulting in an absolute rate reduction of 0.51 episodes (95% CI 0.19-0.84) per patient-year with insulin analogues. This result corresponds to a relative rate reduction of 29% (95% CI 11-48; p=0.010).

INTERPRETATION

Treatment with insulin detemir and aspart in patients with type 1 diabetes and recurrent severe hypoglycaemia resulted in a clinically significant reduced rate of severe hypoglycaemia compared with human insulin. Patients with the greatest chance of benefitting from improved insulin therapy should be offered treatment with insulin analogues and be included in future trials of new insulins.

FUNDING

Novo Nordisk A/S.

Severe hypoglycemia and ketoacidosis over one year in Italian pediatric population with type 1 diabetes mellitus: a multicenter retrospective observational study

BACKGROUND AND AIMS

Evaluation of incidence and correlates of severe hypoglycemia (SH) and diabetes ketoacidosis (DKA) in children and adolescents with T1DM.

METHODS AND RESULTS

Retrospective study conducted in 29 diabetes centers from November 2011 to April 2012. The incidence of SH and DKA episodes and their correlates were assessed through a questionnaire administered to parents of patients aged 0-18 years. Incidence rates and incident rate ratios (IRRs) were estimated through multivariate Poisson regression analysis and multilevel analysis. Overall, 2025 patients were included (age 12.4 ± 3.8 years; 53% males; diabetes duration 5.6 ± 3.5 years; HbA1c 7.9 ± 1.1%). The incidence of SH and DKA were of 7.7 and 2.4 events/100 py, respectively. The risk of SH was higher in females (IRR = 1.44; 95%CI 1.04-1.99), in patients using rapid acting analogues as compared to regular insulin (IRR = 1.48; 95%CI 0.97-2.26) and lower for patients using long acting analogues as compared to NPH insulin (IRR = 0.40; 95%CI 0.19-0.85). No correlations were found between SH and HbA1c levels. The risk of DKA was higher in patients using rapid acting analogues (IRR = 4.25; 95%CI 1.01-17.86) and increased with insulin units needed (IRR = 7.66; 95%CI 2.83-20.74) and HbA1c levels (IRR = 1.63; 95%CI 1.36-1.95). Mother's age was inversely associated with the risk of both SH (IRR = 0.95; 95%CI 0.92-0.98) and DKA (IRR = 0.94; 95%CI 0.88-0.99). When accounting for center effect, the risk of SH associated with the use of rapid acting insulin analogues was attenuated (IRR = 1.48; 95%CI 0.97-2.26); 33% and 16% of the residual variance in SH and DKA risk was explained by center effect.

CONCLUSION

The risk of SH and DKA is mainly associated with treatment modalities and strongly depends on the practice of specialist centers.

A population-based study of risk factors for severe hypoglycaemia in a contemporary cohort of childhood-onset type 1 diabetes

AIMS/HYPOTHESIS

Severe hypoglycaemia is a major barrier to optimising glycaemic control. Recent changes in therapy, however, may have altered the epidemiology of severe hypoglycaemia and its associated risk factors. The aim of this study was to examine the incidence rates and risk factors associated with severe hypoglycaemia in a contemporary cohort of children and adolescents with type 1 diabetes.

METHODS

Subjects were identified from a population-based register containing data on >99% of patients (<16 years of age) who were being treated for type 1 diabetes in Western Australia. Patients attend the clinic approximately every 3 months, where data pertaining to diabetes management, demographics and complications including hypoglycaemia are prospectively recorded. A severe hypoglycaemic event was defined as an episode of coma or convulsion associated with hypoglycaemia. Risk factors assessed included age, duration of diabetes, glycaemic control, sex, insulin therapy, socioeconomic status and calendar year.

RESULTS

Clinical visit data from 1,770 patients, providing 8,214 patient-years of data between 2000 and 2011 were analysed. During follow-up, 841 episodes of severe hypoglycaemia were observed. No difference in risk of severe hypoglycaemia was observed between age groups. Good glycaemic control (HbA1c <7% [53 mmol/mol]) compared with the cohort average (HbA1c 8-9% [64-75 mmol/mol]) was not associated with an increased risk of severe hypoglycaemia. When compared with patients on injection regimens, subjects aged 12-18 years on pump therapy were at reduced risk of severe hypoglycaemia (incidence risk ratio 0.6; 95% CI 0.4, 0.9).

CONCLUSIONS/INTERPRETATION

In this population-based sample of children and adolescents with type 1 diabetes, contemporary therapy is associated with a changed pattern and incidence of severe hypoglycaemia.

Comparison of a soluble co-formulation of insulin degludec/insulin aspart vs biphasic insulin aspart 30 in type 2 diabetes: a randomised trial

OBJECTIVE

Insulin degludec/insulin aspart (IDegAsp) is a soluble co-formulation of insulin degludec (70%) and insulin aspart (IAsp: 30%). Here, we compare the efficacy and safety of IDegAsp, an alternative IDegAsp formulation (AF: containing 45% IAsp), and biphasic IAsp 30 (BIAsp 30).

DESIGN

Sixteen-week, open-label, randomised, treat-to-target trial.

METHODS

Insulin-naive subjects with type 2 diabetes (18-75 years) and a HbA1c of 7-11% were randomised to twice-daily IDegAsp (n=61), AF (n=59) or BIAsp 30 (n=62), all in combination with metformin. Insulin was administered pre-breakfast and dinner (main evening meal) and titrated to pre-breakfast and pre-dinner plasma glucose (PG) targets of 4.0-6.0 mmol/l.

RESULTS

Mean HbA1c after 16 weeks was comparable for IDegAsp, AF and BIAsp 30 (6.7, 6.6 and 6.7% respectively). With IDegAsp, 67% of subjects achieved HbA1c 7.0% Without confirmed hypoglycaemia in the last 4 weeks of treatment compared with 53% (AF) and 40% (BIAsp 30). Mean fasting PG was significantly lower for IDegAsp vs BIAsp 30 (treatment difference (TD): -0.99 mmol/l (95% confidence interval: -1.68; 0.29)) and AF vs BIAsp 30 (TD: -0.88 mmol/l (-1.58; -0.18)). A significant, 58% lower rate of confirmed hypoglycaemia was found for IDegAsp vs BIAsp 30 (rate ratio (RR): 0.42 (0.23; 0.75)); rates were similar for AF vs BIAsp 30 (RR: 0.92 (0.54; 1.57)). IDegAsp and AF had numerically lower rates of nocturnal confirmed hypoglycaemia vs BIAsp 30 (RR: 0.33 (0.09; 1.14) and 0.66 (0.22; 1.93) respectively).

CONCLUSIONS

IDegAsp provided comparable overall glycaemic control to BIAsp 30 with a significantly lower rate of hypoglycaemia.

A prospective randomised cross-over study of the effect of insulin analogues and human insulin on the frequency of severe hypoglycaemia in patients with type 1 diabetes and recurrent hypoglycaemia (the HypoAna trial): study rationale and design

BACKGROUND

Severe hypoglycaemia still represents a significant problem in insulin-treated diabetes. Most patients do not experience severe hypoglycaemia often. However, 20% of patients with type 1 diabetes experience recurrent severe hypoglycaemia corresponding to at least two episodes per year. The effect of insulin analogues on glycaemic control has been documented in large trials, while their effect on the frequency of severe hypoglycaemia is less clear, especially in patients with recurrent severe hypoglycaemia. The HypoAna Trial is designed to investigate whether short-acting and long-acting insulin analogues in comparison with human insulin are superior in reducing the occurrence of severe hypoglycaemic episodes in patients with recurrent hypoglycaemia. This paper reports the study design of the HypoAna Trial.

METHODS/DESIGN

The study is a Danish two-year investigator-initiated, prospective, randomised, open, blinded endpoint (PROBE), multicentre, cross-over trial investigating the effect of insulin analogues versus human insulin on the frequency of severe hypoglycaemia in subjects with type 1 diabetes. Patients are randomised to treatment with basal-bolus therapy with insulin detemir / insulin aspart or human NPH insulin / human regular insulin in random order. The major inclusion criterion is history of two or more episodes of severe hypoglycaemia in the preceding year.

DISCUSSION

In contrast to almost all other studies in this field the HypoAna Trial includes only patients with major problems with hypoglycaemia. The HypoAna Trial will elucidate whether basal-bolus regimen with short-acting and long-acting insulin analogues in comparison with human insulin are superior in reducing occurrence of severe hypoglycaemic episodes in hypoglycaemia prone patients with type 1 diabetes. http://www.clinicaltrials.gov: NCT00346996.

Parental Monitoring, Alcohol, and Marijuana use Among Hispanic and Non-Hispanic White Adolescents: Findings from the Arizona Youth Survey

Parental monitoring serves as a key element in the reduction of adolescent substance use, but little is known about how various monitoring practices relate to different levels of use. This study examined the association between two forms of parental monitoring (parental knowledge and parental supervision) and two substance use outcomes (alcohol and marijuana) for Hispanic and non-Hispanic White eighth graders using the Arizona Youth Survey (n = 11,703). Results demonstrated that parental supervision and parental knowledge protected against alcohol and marijuana use for both ethnic groups, but tests for ethnic differences indicated that parental supervision was more protective against high levels of marijuana use for White youth compared to Hispanic youth. Gender differences were also observed with girls benefitting more from both forms of monitoring compared to boys. However, these effects were dependent on the level of substance use involvement and the substance use outcome.

Acute rheumatic fever associated with household crowding in a developed country

BACKGROUND

Acute rheumatic fever (ARF) and its sequelae, chronic rheumatic heart disease, remain important causes of morbidity and mortality worldwide, but there is little recent information about risk factors. The aim of this study was to examine the association between ARF and household crowding in New Zealand between 1996 and 2005.

METHODS

This ecologic study used hospitalization data and census data to calculate incidence rates by census area unit (CAU). Rates of ARF were examined in relation to individual factors (age, ethnicity) and area factors based on the CAU of home address (household crowding, New Zealand deprivation index, household income, and proportion of children aged 5-14 years). The multivariate relationship between ARF incidence and CAU-based variables was assessed using a zero-inflated negative binomial model.

RESULTS

This study included 1249 new cases of ARF between 1996 and 2005. At the univariate level, ARF rates were associated with household crowding across all age groups and ethnicities. ARF rates were significantly and positively related to household crowding after controlling for age, ethnicity, household income, and the density of children in the neighborhood. The incidence rate ratio was 1.065 (95% confidence interval, 1.052-1.079) for the total population.

CONCLUSIONS

In New Zealand, ARF rates are associated with household crowding at the CAU level. This finding supports action to reduce household crowding to improve health and reduce health inequalities. Our conclusion could be further investigated using a case-control study.

Insulin degludec, an ultra-long-acting basal insulin, once a day or three times a week versus insulin glargine once a day in patients with type 2 diabetes: a 16-week, randomised, open-label, phase 2 trial

BACKGROUND

Insulin degludec is a new basal insulin that forms soluble multihexamer assemblies after subcutaneous injection, resulting in an ultra-long action profile. This study aimed to assess efficacy and safety of insulin degludec injected once a day or three times a week compared with insulin glargine once a day in insulin-naive people with type 2 diabetes, who were inadequately controlled with oral antidiabetic drugs.

METHODS

In this 16-week, randomised, open-label, parallel-group phase 2 trial, participants aged 18–75 years with type 2 diabetes and glycosylated haemoglobin (HbA(1C)) of 7·0–11·0% were enrolled and treated at 28 clinical sites in Canada, India, South Africa, and the USA. Participants were randomly allocated in a 1:1:1:1 ratio by computer-generated block randomisation to receive insulin degludec either once a day or three times a week or insulin glargine once a day, all in combination with metformin. Investigators were masked to data until database release. The primary outcome was HbA(1C) after 16 weeks of treatment. Analyses were done by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00611884.

FINDINGS

Of 367 patients screened, 245 were eligible for inclusion. 62 participants were randomly allocated to receive insulin degludec three times a week (starting dose 20 U per injection [1 U=9 nmol]), 60 to receive insulin degludec once a day (starting dose 10 U [1 U=6 nmol]; group A), 61 to receive insulin degludec once a day (starting dose 10 U [1 U=9 nmol]; group B), and 62 to receive insulin glargine (starting dose 10 U [1 U=6 nmol]) once a day. At study end, mean HbA(1C) levels were much the same across treatment groups, at 7·3% (SD 1·1), 7·4% (1·0), 7·5% (1·1), and 7·2% (0·9), respectively. Estimated mean HbA(1C) treatment differences from insulin degludec by comparison with insulin glargine were 0·08% (95% CI –0·23 to 0·40) for the three dose per week schedule, 0·17% (–0·15 to 0·48) for group A, and 0·28% (–0·04 to 0·59) for group B. Few participants had hypoglycaemia and the number of adverse events was much the same across groups, with no apparent treatment-specific pattern.

INTERPRETATION

Insulin degludec provides comparable glycaemic control to insulin glargine without additional adverse events and might reduce dosing frequency due to its ultra-long action profile.

FUNDING

Novo Nordisk.

Insulin degludec in type 1 diabetes: a randomized controlled trial of a new-generation ultra-long-acting insulin compared with insulin glargine

OBJECTIVE

Insulin degludec (IDeg) is a basal insulin that forms soluble multihexamers after subcutaneous injection, resulting in an ultra-long action profile. We assessed the efficacy and safety of IDeg formulations administered once daily in combination with mealtime insulin aspart in people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

In this 16-week, randomized, open-label trial, participants (mean: 45.8 years old, A1C 8.4%, fasting plasma glucose [FPG] 9.9 mmol/L, BMI 26.9 kg/m(2)) received subcutaneous injections of IDeg(A) (600 μmol/L; n = 59), IDeg(B) (900 μmol/L; n = 60), or insulin glargine (IGlar; n = 59), all given once daily in the evening. Insulin aspart was administered at mealtimes. RESULTS At 16 weeks, mean A1C was comparable for IDeg(A) (7.8 ± 0.8%), IDeg(B) (8.0 ± 1.0%), and IGlar (7.6 ± 0.8%), as was FPG (8.3 ± 4.0, 8.3 ± 2.8, and 8.9 ± 3.5 mmol/L, respectively). Estimated mean rates of confirmed hypoglycemia were 28% lower for IDeg(A) compared with IGlar (rate ratio [RR]: 0.72 [95% CI 0.52-1.00]) and 10% lower for IDeg(B) compared with IGlar (RR: 0.90 [0.65-1.24]); rates of nocturnal hypoglycemia were 58% lower for IDeg(A) (RR: 0.42 [0.25-0.69]) and 29% lower for IDeg(B) (RR: 0.71 [0.44-1.16]). Mean total daily insulin dose was similar to baseline. The frequency and pattern of adverse events was similar between insulin treatments.

CONCLUSIONS

In this clinical exploratory phase 2 trial in people with type 1 diabetes, IDeg is safe and well tolerated and provides comparable glycemic control to IGlar at similar doses, with reduced rates of hypoglycemia.

Variables associated with severe hypoglycemia in children and adolescents with type 1 diabetes: a population-based study

OBJECTIVE

Hypoglycemia remains a central problem in the management of type 1 diabetes mellitus (T1DM) and limits the achievement of good or normal glycemic control. The Diabetes Control and Complication Trial showed that intensive treatment of T1DM increased the risk of severe hypoglycemia (SH) when compared to conventional therapy. The aim of our study was to determine the incidence of SH and associated variables in a population of children and adolescents with T1DM.

RESEARCH DESIGN AND METHODS

We performed a 7.5-yr prospective study enrolling 195 patients aged 13.9 ± 6.6 yr. The study was carried out by referring to the T1DM population-based register in the Abruzzo region of Italy. The incidence of SH, defined as blood glucose levels <50 mg/dL (<2.77 mmol/L) associated with altered states of consciousness (including confusional state, seizures, and coma) was recorded. Glycated hemoglobin (HbA1c) percentage, insulin dose, insulin regimen, time since diagnosis, and age at onset were also recorded.

RESULTS

One hundred and thirty-three severe hypoglycemic events occurred during the study period; the overall incidence was 9.4 episodes per 100 patient-years. Significant predictors of hypoglycemia were diabetes duration >10 yr (p = 0.01), basal/bolus insulin ratio (ratio of daily basal insulin units to daily bolus insulin units) >0.8 (p = 0.01). No relationship was found between hypoglycemic episodes and HbA1c levels, daily insulin requirements, or insulin regimen.

CONCLUSIONS

In these patients, a relatively low incidence of SH was recorded, without pronounced association with lower HbA1c or multiple daily injection insulin therapy. SH seems to be mainly related to management of diabetes. We believe that the main path to SH prevention is through patient and family education in the management of T1DM.

Frequency of biochemical hypoglycaemia in adults with Type 1 diabetes with and without impaired awareness of hypoglycaemia: no identifiable differences using continuous glucose monitoring

OBJECTIVE

Impaired awareness of hypoglycaemia (IAH) is a major risk factor for severe hypoglycaemia in Type 1 diabetes. Although biochemical hypoglycaemia is asserted to be more frequent in IAH, this has not been estimated accurately. The aim of this study was to use Continuous Glucose Monitoring (CGM) to quantify hypoglycaemia in IAH and evaluate its use in identifying impaired awareness of hypoglycaemia.

METHODS

Ninety-five patients with Type 1 diabetes were classified as having normal (n = 74) or impaired awareness (n = 21) using an established method of assessing hypoglycaemia awareness. Hypoglycaemia exposure was assessed prospectively over 9-12 months using weekly 4-point capillary home blood glucose monitoring (HBGM), 5 days of CGM and prospective reporting of severe hypoglycaemia. The frequencies of biochemical and severe hypoglycaemia were compared in patients with normal and impaired awareness of hypoglycaemia.

RESULTS

Patients with impaired awareness had a 3-fold higher incidence of severe hypoglycaemia than those with normal awareness [incidence rate ratio (IRR) 3.37 (95% CI 1.30-8.7); P = 0.01] and 1.6-fold higher incidence of hypoglycaemia on weekly HBGM [IRR 1.63 (95% CI 1.09-2.44); P = 0.02]. No significant differences were observed with CGM [IRR for sensor glucose < or = 3.0 mmol/l 1.47 (95% CI 0.91-2.39); P = 0.12; IRR for sensor glucose < or = 2.2 mmol/l 1.23 (95% CI 0.76-1.98); P = 0.40].

CONCLUSIONS

Patients with Type 1 diabetes with impaired awareness had a 3-fold higher risk of severe hypoglycaemia and 1.6-fold higher incidence of biochemical hypoglycaemia measured with weekly glucose monitoring compared with normal awareness, but 5 days of CGM did not differentiate those with impaired from those with normal awareness.

Determinants of severe hypoglycemia complicating type 2 diabetes: the Fremantle diabetes study

CONTEXT

There are limited published data characterizing severe hypoglycemia complicating type 2 diabetes.

OBJECTIVE

The objective of the study was to determine the incidence and predictors of severe hypoglycemia in community-dwelling type 2 patients.

DESIGN

This was a longitudinal observational cohort study.

SETTING

This was a community-based study.

PATIENTS

There were 616 patients (mean age 67.0 yr, 52.3% males, median diabetes duration 7.7 yr) assessed in 1998 and followed up to the end of June 2006.

MAIN OUTCOME MEASURES

Severe hypoglycemia defined as that requiring ambulance attendance, emergency department services, and/or hospitalization. Cox proportional hazards modeling was used to determine predictors of first episode, and Poisson, negative binomial, zero-inflated Poisson, and zero-inflated negative binomial regression models identified predictors of frequency.

RESULTS

Fifty-two (8.4%) experienced 66 episodes during 3953 patient-years (incidence 1.7 per 100 patient-years). Those experiencing severe hypoglycemia had one to four episodes. Significant independent predictors of time to first episode were duration of insulin treatment, estimated glomerular filtration rate less than 60 ml/min per 1.73 m(2), peripheral neuropathy, education beyond primary level, and past severe hypoglycemia. The zero-inflated negative binomial provided the best model of severe hypoglycemia frequency. Lower fasting serum glucose and higher glycosylated hemoglobin were significantly associated with frequency, whereas patients at minimal risk of repeated severe hypoglycemia were unlikely to use insulin or to have short-duration insulin treatment, to have renal impairment or peripheral neuropathy, or to be educated beyond primary level.

CONCLUSIONS

Duration of insulin treatment was confirmed as an independent risk factor for severe hypoglycemia. The novel association with educational attainment suggests knowledge-driven intensive glycemic self-management. The positive relationship between frequency and glycosylated hemoglobin may identify patients with unstable glycemic control.

Aging and Urbanization: The Neighborhood Perception and Functional Performance of Elderly Persons in Belo Horizonte Metropolitan Area-Brazil

Currently, half of the world population resides in cities. The percentage of world population that is elderly is expected to double from 11% to 22% by 2050 and will be concentrated in urban areas of developing countries. The purpose of this study was to evaluate the functional status of elderly who live in the Belo Horizonte Metropolitan Area, Minas Gerais State, Brazil. The International Classification of Functioning, Disability and Health (ICF) was employed as the theoretical model. Probabilistic sampling was used to select 1,611 elderly persons (defined as >/=60 years) for the study. The response variable "functional performance" was developed by counting the number of basic and instrumental activities of daily living (ADL) that subjects found difficult to carry out. A zero-inflated negative binomial (ZINB) regression model was fitted to the data. The prevalence of disability was 47.1%. Neighborhood self-perception revealed that 84.0% of the elderly were satisfied with their neighborhood, although only 18.4% trusted people around them. Concerns about walking around the neighborhood were: fear of being robbed (78.0%) and fear of falling due to sidewalk defects (48.2%), which caused a 62% increase in the number of ADL carried out with difficulty. It is well known that there is a continuous tendency for functional results to improve as the frequency of walking increases. Thus, urban infrastructure interventions, such as improving public sidewalks, might influence the frequency of elderlies walking in their neighborhoods. Making walking possible-or even pleasant-could increase their social participation and use of services.

Transition to adult care for youths with diabetes mellitus: findings from a Universal Health Care System

OBJECTIVES

The goals were (1) to describe rates of diabetes mellitus (DM)-related hospitalizations and retinopathy screening before and after transition to adult care and (2) to test whether different methods of transfer of care were associated with improved outcomes.

METHODS

In a retrospective cohort study, we included 1507 young adults with DM of >or=5-year duration and tracked these patients until 20 years of age.

RESULTS

DM-related hospitalization rates increased from 7.6 to 9.5 cases per 100 patient-years in the 2 years after transition to adult care (P = .03). Previous DM-related hospitalizations, lower income, female gender, and living in areas with low physician supply were associated with higher admission rates. With controlling for all other factors, individuals who were transferred to a new allied health care team with no change in physician were 23% less likely (relative risk: 0.23 [95% confidence interval: 0.05-0.79]) to be hospitalized after the transition than were those transferred to a new physician with either a new or no allied health care team. The rates of eye examinations were stable across the transition to adult care (72% vs 70%; P = .06). Female patients, patients with higher income, and patients with previous eye care were more likely to have an eye care visit after transfer.

CONCLUSIONS

During the transition to adult health care, there is increased risk of DM-related hospitalizations, although this may be attenuated in youths for whom there is physician continuity. Eye care visits were not related to transition; however, rates were below evidence-based guideline recommendations.

Count data distributions and their zero-modified equivalents as a framework for modelling microbial data with a relatively high occurrence of zero counts

In many cases, microbial data are characterised by a relatively high proportion of zero counts, as occurs with some hygiene indicators and pathogens, which complicates the statistical treatment under the assumption of log normality. The objective of this work was to introduce an alternative Poisson-based distribution framework capable of representing this kind of data without incurring loss of information. The negative binomial, and two zero-modified parameterizations of the Poisson and negative binomial distributions (zero-inflated and hurdle) were fitted to actual zero-inflated bacterial data consisting of total coliforms (n=590) and Escherichia coli (n=677) present on beef carcasses sampled from nine Irish abattoirs. Improvement over the simple Poisson was shown by the simple negative binomial (p=0.426 for chi(2) test for the coliforms data) due to the added heterogeneity parameter, although it slightly overestimated the zero counts and underestimated the first few positive counts for both data sets. Whereas, the zero-modified Poisson could not cope with the data over-dispersion in any of its parameterizations (p<0.001 for chi(2) tests), the parameterizations of the zero-modified negative binomial presented differences in fit due to approximation errors. While the zero-inflated negative binomial parameterization was apparently reduced to a negative binomial due to a non-convergence of the logit parameter estimate, the goodness of fit of the hurdle negative binomial parameterization indicated that for the data sets under evaluation (coliforms data with approximately 13% zero counts and E.coli data with approximately 42% zero counts), the zero-modified negative binomial distribution was comparable to the simpler negative binomial distribution. Thus, bacterial data consisting of a considerable number of zero counts can be appropriately represented by using such count distributions, and this work serves as the starting point for an alternative statistical treatment of this kind of data and stochastic risk assessment modelling.

Predictors of dental caries progression in primary teeth

The current evidence on the role of the social, behavioral, and community determinants of dental caries is based on cross-sectional analyses. The available evidence has not been based on analysis of multiple determinants within the same population. This longitudinal study addresses both of these limitations. The study included data from 788 dyads of children and their caregivers (77% follow-up), who were examined in 2002-03 and 2004-05. The families were assessed by calibrated dentists for severity of caries at both time periods. Additionally, the caregivers answered questionnaires administered by trained interviewers. The caries increment was adjusted for reversals. Significant predictors of higher caries increment were higher consumption of soda drinks, older age of child, greater weight-for-age, fewer dental treatment visits, higher baseline caries levels of children and their caregivers, dental fatalism, and neighborhood disadvantage status. The selected risk factors in the final model explained about 20% of the variation in the increment.

Cariogenicity of soft drinks, milk and fruit juice in low-income african-american children: a longitudinal study

BACKGROUND

The authors conducted a study to test the hypothesis that high consumption of soft drinks, relative to milk and 100 percent fruit juice, is a risk factor for dental caries in low-income African-American children in Detroit.

METHODS

Trained dentists and interviewers examined a representative sample of 369 children, aged 3 to 5 years, in 2002-2003 and again two years later. The authors used the 2000 Block Kids Food Frequency Questionnaire (NutritionQuest, Berkeley, Calif.) to collect dietary information. They assessed caries by using the International Caries Detection and Assessment System.

RESULTS

Soft drinks, 100 percent fruit juice and milk represented the sugared beverages consumed by the cohort. A cluster analysis of the relative proportion of each drink at baseline and follow-up revealed four consumption patterns. Using zero-inflated negative binomial models, the authors found that children who changed from being low consumers of soft drinks at baseline to high consumers after two years had a 1.75 times higher mean number of new decayed, missing and filled tooth surfaces compared with low consumers of soft drinks at both time points.

CONCLUSION

Children who consumed more soft drinks, relative to milk and 100 percent fruit juice, as they grew older were at a greater risk of developing dental caries.

CLINICAL IMPLICATIONS

Health promotion programs and health care providers should emphasize to patients and caregivers the caries risk associated with consumption of soft drinks.

Serum angiotensin-converting enzyme and frequency of severe hypoglycaemia in Type 1 diabetes: does a relationship exist?

AIMS

An association has been described between elevated serum angiotensin-converting enzyme (ACE) and an increased risk of severe hypoglycaemia (SH). To ascertain whether this reported association could be replicated in a different country, it was re-examined in 300 individuals with Type 1 diabetes.

METHODS

People with Type 1 diabetes, none of whom was taking renin-angiotensin system blocking drugs, were recruited. Participants recorded the frequency with which they had experienced SH. Glycated haemoglobin (HbA(1c)) and serum ACE were measured. The difference in the incidence of SH between different quartiles of ACE activity and the relationship between serum ACE and SH were examined using non-parametric statistical tests and a negative binomial model.

RESULTS

Data were obtained from 300 patients [158 male; HbA(1c) median (range) 8.2% (5.2-12.8%), median age 36 years (16-88); duration of diabetes 14.5 years (2-49)]. The incidence of SH was 0.93 episodes per patient year. The mean incidence of SH in the top and bottom quartiles of ACE activity was 0.5 and 1.7 episodes per patient year, respectively, but this difference was not statistically significant (P = 0.075). Spearman's test showed a very weak, although statistically significant, association between serum ACE level and SH incidence (r = 0.115, P = 0.047). The binomial model also showed a statistically significant (P = 0.002), but clinically weak, relationship between serum ACE and SH.

CONCLUSIONS

The present survey showed a weak relationship between serum ACE and the frequency of SH, the clinical relevance of which is unclear. This limits the proposed role for serum ACE as an index of risk for SH.

The relationship between ACE genotype and risk of severe hypoglycaemia in a large population-based cohort of children and adolescents with type 1 diabetes

AIMS/HYPOTHESIS

Genetic factors may account for familial clustering related to diabetes complications. Studies have shown a significant relationship between the presence of the deletion (D) allele of the gene encoding ACE and risk of severe hypoglycaemia. This large prospective cohort study assesses this relationship in a large sample of children and adolescents with type 1 diabetes.

SUBJECTS AND METHODS

We studied 585 children and adolescents (mean age 11.9 +/- 4 years, 48.4% males). The frequency of severe hypoglycaemia (an event leading to loss of consciousness or seizure) was prospectively assessed over the 13-year period 1992-2004. Patients were seen with their parents every 3 months and data recorded at each visit. The ACE gene was detected using PCR.

RESULTS

In our cohort of 585 children, 186 (31.8%) had at least one episode of severe hypoglycaemia, and of these 28.0% had the II genotype, 48.9% had the ID genotype and 23.1% had the DD genotype. This was in agreement with the Hardy-Weinberg proportion. A total of 477 severe hypoglycaemic episodes was recorded with a total of 3,404 person-years of follow-up, giving a total incidence of 14 per 100 patient-years. No significant increase in risk for DD genotype (incidence rate ratio = 0.97, 95% CI 0.61-1.55) relative to II genotype was observed.

CONCLUSIONS/INTERPRETATION

This large prospective study concludes that the presence of the D allele of the ACE gene does not predict a significantly higher risk of severe hypoglycaemia in type 1 diabetic children and adolescents.

Frequency and risk factors of severe hypoglycaemia in insulin-treated Type 2 diabetes: a cross-sectional survey

AIMS

The reported risk of severe hypoglycaemia in insulin-treated Type 2 diabetes is highly variable and few studies have evaluated the influence of risk factors. We assessed the incidence and the influence of potential risk factors for severe hypoglycaemia in a questionnaire survey in subjects with insulin-treated Type 2 diabetes receiving currently recommended multifactorial intervention.

METHODS

Consecutive patients with insulin-treated Type 2 diabetes (n = 401) completed a questionnaire about occurrence of hypoglycaemia in the past, hypoglycaemia awareness and socio-demographic factors. A zero-inflated negative binomial model was used to assess the influence of potential risk factors on the rate of severe hypoglycaemia.

RESULTS

The overall incidence of severe hypoglycaemia in the preceding year was 0.44 episodes/person year. Sixty-six (16.5%) patients had experienced at least one event. The risk of any episode of severe hypoglycaemia positively correlated with impaired hypoglycaemia awareness, being married and long duration of diabetes. The risk of repeated episodes of severe hypoglycaemia positively correlated with the presence of peripheral neuropathy, while long duration of diabetes prior to insulin treatment and treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor antagonists (ARBs) were associated with reduced risk. C-peptide concentration and HbA1c were not associated with the risk of severe hypoglycaemia.

CONCLUSIONS

In this cohort of insulin-treated Type 2 diabetic patients, the incidence of severe hypoglycaemia is higher than reported in most studies, corresponding to about one-third of that in Type 1 diabetes. Impaired hypoglycaemia awareness is the most important risk factor for severe hypoglycaemia.

A demonstration of modeling count data with an application to physical activity

Counting outcomes such as days of physical activity or servings of fruits and vegetables often have distributions that are highly skewed toward the right with a preponderance of zeros, posing analytical challenges. This paper demonstrates how such outcomes may be analyzed with several modifications to Poisson regression.

Five regression models 1) Poisson, 2) overdispersed Poisson, 3) negative binomial, 4) zero-inflated Poisson (ZIP), and 5) zero-inflated negative binomial (ZINB) are fitted to data assessing predictors of vigorous physical activity (VPA) among Latina women. The models are described, and analytical and graphical approaches are discussed to aid in model selection.

Poisson regression provided a poor fit where 82% of the subjects reported no days of VPA. The fit improved considerably with the negative binomial and ZIP models. There was little difference in fit between the ZIP and ZINB models. Overall, the ZIP model fit best. No days of VPA were associated with poorer self-reported health and less assimilation to Anglo culture, and marginally associated with increasing BMI. The intensity portion of the model suggested that increasing days of VPA were associated with more education, and marginally associated with increasing age. These underutilized models provide useful approaches for handling counting outcomes.

Hypoglycemia: a complication of diabetes therapy in children

The experience of hypoglycemia is probably the most feared and hated consequence of life with type 1 diabetes among pediatric patients and their parents. Although transient detrimental effects are clearly disturbing and may have severe results, there is surprisingly little evidence of long-term CNS damage, even after multiple hypoglycemic episodes, except in rare instances. Despite the latter evidence, we advocate that every treatment regimen be designed to prevent hypoglycemia without inducing unacceptable hyperglycemia and increasing the risk of micro- and macrovascular complications.

The impact of a decade of changing treatment on rates of severe hypoglycemia in a population-based cohort of children with type 1 diabetes

OBJECTIVE

To determine the impact of changes to treatment on the incidence of severe hypoglycemia and its risk factors in a large population-based cohort of children with type 1 diabetes.

RESEARCH DESIGN AND METHODS

The cohort consisted of 1,335 children (age at entry 9.5 +/- 4.3 years [mean +/- SD], range 0-18), yielding 6,928 patient-years of data. The mean follow-up period was 4.7 +/- 3.1 years (range 0-10.7). Prospective assessment of severe hypoglycemia (an event leading to loss of consciousness or seizure) and associated clinical factors and outcomes was made between 1992 and 2002. Patients were reviewed every 3 months. Data were analyzed using the negative binomial regression model.

RESULTS

A total of 944 severe events were recorded. The incidence of severe hypoglycemia increased significantly by 29% per year for the first 5 years but appeared to plateau over the last 5 years. The overall average HbA1c significantly decreased (by 0.2% per year) over the whole follow-up period. An increased risk of severe hypoglycemia was associated with lower HbA1c, younger age, higher insulin dose, male sex, and lower parental socioeconomic status. Of insulin therapies, only pump treatment was associated with reduced rates of severe hypoglycemia.

CONCLUSIONS

Severe hypoglycemia remains a major problem for children and adolescents with type 1 diabetes. Recent approaches to therapy may be allowing a degree of improved control without the expected increased risk of severe hypoglycemia but further monitoring will be important.