End-stage renal disease and chronic kidney disease in a cohort of African-American HIV-infected and at-risk HIV-seronegative participants followed between 1988 and 2004

Identifying the appropriate comparison group for HIV-infected individuals

PURPOSE OF REVIEW

HIV-infected individuals are living longer as a result of effective treatment. Age-related comorbidities now account for the majority of morbidity and mortality among treated HIV-infected adults. Previous findings regarding the age at, and risk of, these comorbidities have been mixed, sparking debate in the field. Discerning potential differences in the occurrence and burden of age-related comorbidities among treated HIV-infected adults as compared with uninfected adults of the same age requires careful selection of the appropriate uninfected comparison group.

RECENT FINDINGS

The validity of comparisons with HIV-uninfected populations is threatened when differences in demographic, clinical, and lifestyle characteristics between HIV-infected and uninfected adults are not considered. Identifying a pool of HIV-uninfected individuals from existing secondary data resources and employing selection methodologies may be a novel approach to reduce threats to internal validity. Issues related to identifying data sources, understanding inclusion criteria, determining measurement error, and threats to inference are discussed.

SUMMARY

The development of clinical interventions targeting age-related comorbidities will rely on deriving valid inferences from appropriate comparison groups. The use of secondary data resources and selection methodology to create the appropriate uninfected comparison group is an attractive approach in the setting of finite resources, but are not without limitations.

Predictors of HIV-associated nephropathy

Renal disease accounts for significant morbidity and mortality in patients with HIV-1 infection. HIV-associated nephropathy (HIVAN) is an important cause of end stage renal disease in this population. Although multiple genetic, clinical, and laboratory characteristics such as Apolipoproetin-1 genetic polymorphism, high viral load, low CD-4 count, nephrotic range proteinuria, and increased renal echogenicity on ultrasound are predictive of HIVAN, kidney biopsy remains the gold standard to make the definitive diagnosis. Current treatment options for HIVAN include initiation of combined active antiretroviral therapy, blockade of the renin-angiotensin system, and steroids. In patients with progression of HIVAN, renal transplant should be pursued as long as their systemic HIV infection is controlled.

The changing epidemiology of HIV-related chronic kidney disease in the era of antiretroviral therapy

The epidemiology of kidney disease in HIV-infected individuals has changed significantly since the introduction of combination antiretroviral therapy (cART) in the mid 1990s. HIV-associated nephropathy (HIVAN), an aggressive form of collapsing focal segmental glomerulosclerosis (FSGS) caused by direct HIV infection of the kidney in a genetically susceptible host, emerged early in the HIV epidemic as a leading cause of end-stage renal disease. With the widespread use of cART, HIVAN is increasingly rare in populations with access to care, and the spectrum of HIV-related chronic kidney disease now reflects the growing burden of comorbid disease in the aging HIV population. Nonetheless, available data suggest that both HIV infection and cART nephrotoxicity continue to contribute to the increased risk of chronic kidney disease in HIV-infected individuals in the United States and Europe. Despite the genetic susceptibility to HIVAN in individuals of West African descent, limited data are available to define the prevalence and spectrum of HIV-related kidney disease in sub-Saharan Africa, which is home to two-thirds of the world's HIV population. In this mini-review, we characterize the changing epidemiology of HIV-related chronic kidney disease in Western nations and in sub-Saharan Africa.

Predictors of advanced chronic kidney disease and end-stage renal disease in HIV-positive persons

OBJECTIVES

Whilst several antiretroviral drugs have been associated with moderate chronic kidney disease (CKD), their contribution to advanced CKD and end-stage renal disease (ESRD) remain unknown.

DESIGN

D:A:D participants with at least three estimated glomerular filtration rates (eGFR) after February 2004 were followed until the first of advanced CKD (confirmed eGFR ≤ 30 ml/min, ≥3 months apart), ESRD (dialysis ≥3 months/ transplantation), 6 months after last visit or February 2012.

METHODS

Poisson regression was used to assess risk factors for advanced CKD/ESRD including exposure to potential nephrotoxic antiretroviral drugs and antiretroviral drug discontinuation rates according to latest eGFR.

RESULTS

Among 35 192 persons contributing 200 119 person years of follow-up (PYFU), 135 (0.4%) developed advanced CKD (n = 114)/ESRD (n = 21); incidence rate = 0.67 [95% confidence interval (CI), 0.56-0.79]/1000 PYFU. Tenofovir (TDF) was particularly frequently discontinued as eGFR declined. After adjustment, those previously exposed but currently off TDF had similar advanced CKD/ESRD rate ratios compared with those unexposed [1.00 (95% CI, 0.66-1.51)], while those currently on TDF had reduced rates [0.23 (95% CI, 0.13-0.41)]. No consistent associations with other antiretroviral drugs were seen. Results were robust after time-lagging antiretroviral drug exposure, stratifying by baseline eGFR, and allowing for competing risks. Other predictors were diabetes, hypertension, baseline eGFR, smoking and current CD4 cell count. The incidence rate in nonsmokers with baseline eGFR > 60 and no diabetes or hypertension was 0.16 (95% CI 0.09-0.26)/1000 PYFU.

CONCLUSION

Neither current nor recent antiretroviral drug use predicted advanced CKD/ESRD during 6 years median follow-up in a large, heterogenenous and primarily white cohort. TDF discontinuation rates increased with decreasing eGFR, leaving a selected group still on TDF at lower advanced CKD/ESRD risk. Traditional renal risk factors and current CD4 cell count were the strongest advanced CKD/ESRD predictors.

The next therapeutic challenge in HIV: polypharmacy

With the adoption of combination antiretroviral therapy (ART), most HIV-infected individuals in care are on five or more medications and at risk of harm from polypharmacy, a risk that likely increases with number of medications, age, and physiologic frailty. Established harms of polypharmacy include decreased medication adherence and increased serious adverse drug events, including organ system injury, hospitalization, geriatric syndromes (falls, fractures, and cognitive decline) and mortality. The literature on polypharmacy among those with HIV infection is limited, and the literature on polypharmacy among non-HIV patients requires adaptation to the special issues facing those on chronic ART. First, those aging with HIV infection often initiate ART in their 3rd or 4th decade of life and are expected to remain on ART for the rest of their lives. Second, those with HIV may be at higher risk for age-associated comorbid disease, further increasing their risk of polypharmacy. Third, those with HIV may have an enhanced susceptibility to harm from polypharmacy due to decreased organ system reserve, chronic inflammation, and ongoing immune dysfunction. Finally, because ART is life-extending, nonadherence to ART is particularly concerning. After reviewing the relevant literature, we propose an adapted framework with which to address polypharmacy among those on lifelong ART and suggest areas for future work.

Advanced chronic kidney disease, end-stage renal disease and renal death among HIV-positive individuals in Europe

OBJECTIVES

Knowledge about advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) in HIV-positive persons is limited. The aim of this study was to investigate incidence, predictors and outcomes for advanced CKD/ESRD and renal death.

METHODS

Advanced CKD was defined as confirmed (two consecutive measurements ≥ 3 months apart) estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m(2) using Cockcroft-Gault, and ESRD as haemodialysis or peritoneal dialysis for ≥ 1 month or renal transplant. Renal death was death with renal disease as the underlying cause, using Coding Causes of Death in HIV (CoDe) methodology. Follow-up was from 1 January 2004 until last eGFR measurement, advanced CKD, ESRD or renal death, whichever occurred first. Poisson regression was used to identify predictors.

RESULTS

Of 9044 individuals included in the study, 58 (0.64%) experienced advanced CKD/ESRD/renal death [incidence rate 1.32/1000 person-years of follow-up (PYFU); 95% confidence interval (CI) 0.98-1.66]; 52% of those who experienced the endpoint had a baseline eGFR ≤ 60 mL/min/1.73 m(2) compared with 3% of those who did not. Using Kaplan-Meier methods, at 6 years from baseline, 0.83% (95% CI 0.59-1.07%) were estimated to have experienced the endpoint overall and 11.26% (95% CI 6.75-15.78%) among those with baseline eGFR ≤ 60 mL/min/1.73 m(2) . Independent predictors of the endpoint included any cardiovascular event [incidence rate ratio (IRR) 2.16; 95% CI 1.24-3.77], lower eGFR (IRR 0.64 per 5 mL/min/1.73 m(2) ; 95% CI 0.59-0.70) and lower CD4 count (IRR 0.77 per doubling; 95% CI 0.62-0.95). One year after experiencing advanced CKD or ESRD, an estimated 19.21% (95% CI 7.84-30.58%) of patients had died, mostly from extra-renal causes.

CONCLUSIONS

The incidence of advanced CKD/ESRD/renal death was low and predictors included traditional renal risk factors, HIV-related factors and pre-existing renal impairment. The prognosis following advanced CKD/ESRD was poor. Larger studies should address possible contributions of specific antiretrovirals.

Renoprotective effect of combined inhibition of angiotensin-converting enzyme and histone deacetylase

The Connectivity Map database contains microarray signatures of gene expression derived from approximately 6000 experiments that examined the effects of approximately 1300 single drugs on several human cancer cell lines. We used these data to prioritize pairs of drugs expected to reverse the changes in gene expression observed in the kidneys of a mouse model of HIV-associated nephropathy (Tg26 mice). We predicted that the combination of an angiotensin-converting enzyme (ACE) inhibitor and a histone deacetylase inhibitor would maximally reverse the disease-associated expression of genes in the kidneys of these mice. Testing the combination of these inhibitors in Tg26 mice revealed an additive renoprotective effect, as suggested by reduction of proteinuria, improvement of renal function, and attenuation of kidney injury. Furthermore, we observed the predicted treatment-associated changes in the expression of selected genes and pathway components. In summary, these data suggest that the combination of an ACE inhibitor and a histone deacetylase inhibitor could have therapeutic potential for various kidney diseases. In addition, this study provides proof-of-concept that drug-induced expression signatures have potential use in predicting the effects of combination drug therapy.

Urinary markers of kidney injury and kidney function decline in HIV-infected women

OBJECTIVE

HIV-infected persons have substantially higher risk of kidney failure than persons without HIV, but serum creatinine levels are insensitive for detecting declining kidney function. We hypothesized that urine markers of kidney injury would be associated with declining kidney function among HIV-infected women.

METHODS

In the Women's Interagency HIV Study, we measured concentrations of albumin-to-creatinine ratio, interleukin-18 (IL-18), kidney injury marker-1 (KIM-1), and neutrophil gelatinase-associated lipocalin from stored urine among 908 HIV-infected and 289 HIV-uninfected participants. Primary analyses used cystatin C-based estimated glomerular filtration rate (CKD-EPI eGFRcys) as the outcome, measured at baseline and 2 follow-up visits over 8 years; secondary analyses used creatinine (CKD-EPI eGFRcr). Each urine biomarker was categorized into tertiles, and kidney decline was modeled with both continuous and dichotomized outcomes.

RESULTS

Compared with the lowest tertiles, the highest tertiles of albumin-to-creatinine ratio (-0.15 mL/min per 1.73 m, P < 0.0001), IL-18 (-0.09 mL/min per 1.73 m, P < 0.0001) and KIM-1 (-0.06 mL/min per 1.73 m, P < 0.001) were independently associated with faster eGFRcys decline after multivariate adjustment including all 3 biomarkers among HIV-infected women. Among these biomarkers, only IL-18 was associated with each dichotomized eGFRcys outcome: ≥3% (relative risk = 1.40; 95% confidence interval: 1.04 to 1.89); ≥5% (1.88; 1.30 to 2.71); and ≥10% (2.16; 1.20 to 3.88) for the highest versus lowest tertile. In alternative models using eGFRcr, the high tertile of KIM-1 had independent associations with 5% (1.71; 1.25 to 2.33) and 10% (1.78; 1.07 to 2.96) decline, and the high IL-18 tertile with 10% decline (1.97; 1.00 to 3.87).

CONCLUSIONS

Among HIV-infected women in the Women's Interagency HIV Study cohort, novel urine markers of kidney injury detect risk for subsequent declines in kidney function.

Chronic kidney disease at presentation is not an independent risk factor for AIDS-defining events or death in HIV-infected persons

Studies have documented an association between chronic kidney disease (CKD) and increased risk of end stage renal disease, death and comorbidities, including cardiovascular disease and metabolic syndrome, in the general population. However, there is little data on the relationship between CKD and ADE (AIDS defining event), and to our knowledge, no studies have analyzed death as a competing risk for ADE among HIV-infected persons. An observational cohort study was performed to determine the incidence and risks for developing an ADE or death among HIV-infected persons with and without CKD from 1998 - 2005. CKD was defined as an estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73 m2 using the CKDEpidemiology Collaboration (CKD-EPI) equation. Log rank test and Cox regression which determined time to development of ADE and/or death as combined and separate outcomes, and competing risk models for ADE versus mortality, were performed. Among the 2,127 persons that contributed to the 5,824 person years of follow-up: 22% were female, 34% African American, 38% on HAART, and 3% had CKD at baseline. ADE occurred in 227 (11%) persons and there were 80 (4%) deaths. CKD was not significantly associated with ADE/death (HR 1.3, 95% CIs: 0.5, 3.2), ADE (HR 1.0, 95% CIs: 0.4, 3.1), or death (HR 1.6, 95% CIs: 0.4, 3.1). Competing risk analyses confirmed no statistically significant associations between CKD and these outcomes. CKD was uncommon in HIV-infected persons presenting for care in this racially diverse cohort, and was not independently associated with risk of developing an ADE or dying during follow-up.

Renal AA-amyloidosis in intravenous drug users--a role for HIV-infection?

Background

Chronic renal disease is a serious complication of long-term intravenous drug use (IVDU). Recent reports have postulated a changing pattern of underlying nephropathy over the last decades.

Methods

Retrospective investigation including all patients with prior or present IVDU that underwent renal biopsy because of chronic kidney disease between 01.04.2002 and 31.03.2012 in the city of Frankfurt/Main, Germany.

Results

Twenty four patients with IVDU underwent renal biopsy because of progressive chronic kidney disease or proteinuria. Renal AA-amyloidosis was the predominant cause of renal failure in 50% of patients. Membranoproliferative glomerulonephritis (GN) was the second most common cause found in 21%. Patients with AA-amyloidosis were more likely to be HIV infected (67 vs.17%; p=0.036) and tended to have a higher rate of repeated systemic infections (92 vs. 50%; p=0.069). Patients with AA-amyloidosis presented with progressive renal disease and nephrotic-range proteinuria but most patients had no peripheral edema or systemic hypertension. Development of proteinuria preceded the decline of GFR for approximately 1–2 years.

Conclusions

AA-amyloidosis was the predominant cause of progressive renal disease in the last 10 years in patients with IVDU. The highest rate of AA-amyloidosis observed was seen in HIV infected patients with IVDU. We speculate that chronic HIV-infection as well as the associated immunosuppression might promote development of AA-amyloidosis by increasing frequency and duration of infections acquired by IVDU.

Disparities in prevalence of key chronic diseases by gender and race/ethnicity among antiretroviral-treated HIV-infected adults in the US

BACKGROUND

Certain sociodemographic subgroups of HIV-infected patients may experience more chronic disease than others due to behavioural risk factors, advanced HIV disease or complications from extended use of combination antiretroviral therapy (cART), but recent comparative data are limited.

METHODS

We studied HIV-infected adult patients in care during 2006-2010 who had been prescribed ≥ 6 months of cART. We analysed the prevalence of selected key chronic conditions and polymorbidity (having 2 or more out of 10 key conditions) by gender and race/ethnicity.

RESULTS

Of the 3,166 HIV-infected patients (median age 47 years, CD4⁺ T-cell count 496 cells/mm³, duration of cART use 6.8 years), 21% were female, 57% were non-Hispanic White and over half were current or former tobacco smokers. The five most frequent conditions among women (median age 45 years) were dyslipidaemia (67.3%), hypertension (57.4%), obesity (31.7%), viral hepatitis B or C coinfection (29.0%) and low high-density lipoprotein cholesterol (HDLc; 27.3%). The five most frequent conditions in men (median age 47 years) were dyslipidaemia (81.2%), hypertension (54.4%), low HDLc (41.1%), elevated triglycerides (32.3%) and elevated non-HDLc (26.8%). In multivariable analyses, Hispanic patients had higher prevalence of obesity and diabetes than White patients; Black patients had higher prevalence of obesity and hypertension but lower rates of lipid abnormalities. Of all patients, 73.7% of women and 66.8% of men had polymorbidity, with no evidence of disparities by race/ethnicity.

CONCLUSIONS

Among contemporary cART-treated HIV-infected adults, chronic conditions and polymorbidity were common, underscoring the importance of chronic disease prevention and management among ageing HIV-infected patients.

How to manage HIV-infected patients with chronic kidney disease in the HAART era

As human immunodeficiency virus (HIV)-infected patients now live longer while receiving highly active antiretroviral therapy (HAART), chronic kidney disease (CKD) has emerged as a significant cause of morbidity and mortality among urban HIV population. Risk factors associated with CKD in such HIV-infected population include aging, hypertension, diabetes mellitus, co-infection with hepatitis C virus, low CD4 cell count, and high HIV viral load. Clinical experience has shown that HIV-infected individuals often have one or more concurrent risk factors for CKD. The cumulative effect of multiple risk factors on the development of CKD should be noted in this population. Glomerular disease directly related to HIV infection, so-called HIV-associated nephropathy, remains an important cause of CKD among limited HIV population of African descent. The impact of exposure to nephrotoxic antiretroviral agents on the development of kidney disease is both an old and a new concern. In particular, the association of tenofovir with kidney disease has been an area of great interest. The findings regarding tenofovir's adverse effect on long-term kidney function vary among studies. Early identification and treatment of kidney disease is imperative for reducing the burden of patients requiring dialysis in HIV-infected populations. Periodic monitoring of urinary albumin excretion, tubular parameters such as low-molecular-weight proteinuria, and the estimated glomerular filtration rate may be useful for early diagnosis of patients at risk for incident CKD. This review focuses on recent developments in epidemiology, risk factors, identification, estimation, and management of CKD in HIV-infected population in the HAART era.

Kidney Disease in HIV-Infected Persons

Kidney disease is more prevalent among persons living with HIV, and may arise from a combination of comorbidities, co-infections, and medication-associated toxicities. Additional effects of HIV-1 viral replication, immunodeficiency and genetic factors also contribute to kidney disease. As is true in the general population, persons of African descent exhibit a disproportionate risk for severe kidney disease. Antiretroviral therapy (ART) modifies the natural history of HIV-associated nephropathy (HIVAN), and renal benefits of ART may not be limited to persons with HIVAN. Robust associations between proteinuria and cardiovascular disease imply that common mechanisms of vascular endothelial dysfunction may contribute to both processes.

Baseline kidney function as predictor of mortality and kidney disease progression in HIV-positive patients

BACKGROUND

Chronic kidney disease (CKD) is associated with increased all-cause mortality and kidney disease progression. Decreased kidney function at baseline may identify human immunodeficiency virus (HIV)-positive patients at increased risk of death and kidney disease progression.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

7 large HIV cohorts in the United Kingdom with kidney function data available for 20,132 patients.

PREDICTOR

Baseline estimated glomerular filtration rate (eGFR).

OUTCOMES

Death and progression to stages 4-5 CKD (eGFR <30 mL/min/1.73 m(2) for >3 months) in Cox proportional hazards and competing-risk regression models.

RESULTS

Median age at baseline was 34 (25th-75th percentile, 30-40) years, median CD4 cell count was 350 (25th-75th percentile, 208-520) cells/μL, and median eGFR was 100 (25th-75th percentile, 87-112) mL/min/1.73 m(2). Patients were followed up for a median of 5.3 (25th-75th percentile, 2.0-8.9) years, during which 1,820 died and 56 progressed to stages 4-5 CKD. A U-shaped relationship between baseline eGFR and mortality was observed. After adjustment for potential confounders, eGFRs <45 and >105 mL/min/1.73 m(2) remained associated significantly with increased risk of death. Baseline eGFR <90 mL/min/1.73 m(2) was associated with increased risk of kidney disease progression, with the highest incidence rates of stages 4-5 CKD (>3 events/100 person-years) observed in black patients with eGFR of 30-59 mL/min/1.73 m(2) and those of white/other ethnicity with eGFR of 30-44 mL/min/1.73 m(2).

LIMITATIONS

The relatively small numbers of patients with decreased eGFR at baseline and low rates of progression to stages 4-5 CKD and lack of data for diabetes, hypertension, and proteinuria.

CONCLUSIONS

Although stages 4-5 CKD were uncommon in this cohort, baseline eGFR allowed the identification of patients at increased risk of death and at greatest risk of kidney disease progression.

End-stage renal disease and dialysis in HIV-positive patients: observations from a long-term cohort study with a follow-up of 22 years

OBJECTIVES

Renal disease is a common and serious complication in HIV-infected patients.

METHODS

A retrospective cohort analysis for the period 1989-2010 was carried out to determine the prevalence, incidence and risk factors for end-stage renal disease (ESRD). ESRD was defined as initiation of renal replacement therapy. Three time periods were defined: 1989-1996 [pre-highly active antiretroviral therapy (HAART)], 1997-2003 (early HAART) and 2004-2010 (late HAART).

RESULTS

Data for 9198 patients [78.2% male; 88.9% Caucasian; cumulative observation time 68 084 patient-years (PY)] were analysed. ESRD was newly diagnosed in 35 patients (0.38%). Risk factors for ESRD were Black ethnicity [relative risk (RR) 5.1; 95% confidence interval (CI) 2.3-10.3; P < 0.0001], injecting drug use (IDU) (RR 2.3; 95% CI 1.1-4.6; P = 0.02) and hepatitis C virus (HCV) coinfection (RR 2.2; 95% CI 1.1-4.2; P = 0.03). The incidence of ESRD decreased in Black patients over the three time periods [from 788.8 to 130.5 and 164.1 per 100 000 PY of follow-up (PYFU), respectively], but increased in Caucasian patients (from 29.9 to 41.0 and 43.4 per 100 000 PYFU, respectively). The prevalence of ESRD increased over time and reached 1.9 per 1000 patients in 2010. Mortality for patients with ESRD decreased nonsignificantly from period 1 to 2 (RR 0.72; P = 0.52), but significantly from period 1 to 3 (RR 0.24; P = 0.006), whereas for patients without ESRD mortality decreased significantly for all comparisons. ESRD was associated with a high overall mortality (RR 9.9; 95% CI 6.3-14.5; P < 0.0001).

CONCLUSION

As a result of longer survival, the prevalence of ESRD is increasing but remains associated with a high mortality. The incidence of ESRD declined in Black but not in Caucasian patients. IDU and HCV were identified as additional risk factors for the development of ESRD.

HIV and aging: state of knowledge and areas of critical need for research. A report to the NIH Office of AIDS Research by the HIV and Aging Working Group

HIV risk behaviors, susceptibility to HIV acquisition, progression of disease after infection, and response to antiretroviral therapy all vary by age. In those living with HIV, current effective treatment has increased the median life expectancy to >70 years of age. Biologic, medical, individual, social, and societal issues change as one ages with HIV infection, but there has been only a small amount of research in this field. Therefore, the Office of AIDS Research of the National Institutes of Health commissioned a working group to develop an outline of the current state of knowledge and areas of critical need for research in HIV and Aging; the working groups' findings and recommendations are summarized in this report. Key overarching themes identified by the group included the following: multimorbidity, polypharmacy, and the need to emphasize maintenance of function; the complexity of assessing HIV versus treatment effects versus aging versus concurrent disease; the inter-related mechanisms of immune senescence, inflammation, and hypercoagulability; the utility of multivariable indices for predicting outcomes; a need to emphasize human studies to account for complexity; and a required focus on issues of community support, caregivers, and systems infrastructure. Critical resources are needed to enact this research agenda and include expanded review panel expertise in aging, functional measures, and multimorbidity, and facilitated use and continued funding to allow long-term follow-up of cohorts aging with HIV.

Determinants of incident chronic kidney disease and progression in a cohort of HIV-infected persons with unrestricted access to health care

OBJECTIVES

As socioeconomic factors may impact the risk of chronic kidney disease (CKD), we evaluated the incidence and risk factors of incident CKD among an HIV-infected cohort with universal access to health care and minimal injecting drug use (IDU).

METHODS

Incident CKD was defined as an estimated glomerular filteration rate (eGFR) <60 ml/min/1.73 m(2) for ≥ 90 days. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Rates were calculated per 1000 person-years (PY). Associations with outcomes were assessed using two separate Cox proportional hazard models, adjusting for baseline and time-updated covariates.

RESULTS

Among 3360 participants [median age 29 years; 92% male; 44% African American (AA)] contributing 23,091 PY of follow-up, 116 developed incident CKD [5.0/1000 PY; 95% confidence interval (CI) 4.2-6.0/1000 PY]. The median first eGFR value was 97.0 mL/min/1.73 m(2) [interquartile range (IQR) 85.3-110.1 mL/min/1.73 m(2)]. Baseline factors associated with CKD included older age, lower CD4 count at HIV diagnosis [compared with CD4 count ≥ 500 cells/μL, hazard ratio (HR) 2.1 (95% CI 1.2-3.8) for CD4 count 350-499 cells/μL; HR 3.6 (95% CI 2.0-6.3) for CD4 count 201-349 cells/μL; HR 4.3 (95% CI 2.0-9.4) for CD4 count ≤ 200 cells/μL], and HIV diagnosis in the pre-highly active antiretroviral therapy (HAART) era. In the time-updated model, low nadir CD4 counts, diabetes, hepatitis B, hypertension and less HAART use were also associated with CKD. AA ethnicity was not associated with incident CKD in either model.

CONCLUSIONS

The low incidence of CKD and the lack of association with ethnicity observed in this study may in part be attributable to unique features of our cohort such as younger age, early HIV diagnosis, minimal IDU, and unrestricted access to care. Lower baseline CD4 counts were significantly associated with incident CKD, suggesting early HIV diagnosis and timely introduction of HAART may reduce the burden of CKD.

Risk factors for ESRD in HIV-infected individuals: traditional and HIV-related factors

BACKGROUND

Despite improvements in survival with human immunodeficiency virus (HIV) infection, kidney disease remains an important complication. Few studies have evaluated risk factors associated with the development of end-stage renal disease (ESRD) in HIV-infected individuals. We sought to identify traditional and HIV-related risk factors for ESRD in HIV-infected individuals and compare ESRD risk by estimated glomerular filtration rate (eGFR) and proteinuria levels.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

22,156 HIV-infected veterans without pre-existing ESRD receiving health care in the Veterans' Affairs medical system between 1996 and 2004.

PREDICTORS

Hypertension, diabetes, cardiovascular disease, hypoalbuminemia (serum albumin <3.5 mg/dL), CD4 lymphocyte count, HIV viral load, hepatitis C virus coinfection, proteinuria, and eGFR were identified using the Veterans' Affairs electronic record system.

OUTCOMES

ESRD was ascertained by the US Renal Data System.

RESULTS

366 cases of ESRD occurred, corresponding to 3 cases/1,000 person-years. Hypertension (HR, 1.9; 95% CI, 1.5-2.4), diabetes (HR, 1.7; 95% CI, 1.3-2.2), and cardiovascular disease (HR, 2.2; 95% CI, 1.7-2.7) were associated independently with ESRD risk in multivariate-adjusted models, as were CD4 lymphocyte count <200 cells/μL (HR, 1.5; 95% CI, 1.2-2.0), HIV viral load ≥30,000 copies/mL (HR, 2.0; 95% CI, 1.5-2.8), hepatitis C virus coinfection (HR, 1.9; 95% CI, 1.5-2.4), and hypoalbuminemia (HR, 2.1; 95% CI, 1.8-2.5). Compared with persons without chronic kidney disease, defined as eGFR >60 mL/min/1.73 m(2) and no proteinuria, lower eGFR and higher proteinuria categories were associated jointly with exponentially higher ESRD rates, ranging from 6.6 events/1,000 person-years for persons with urine protein excretion of 30-100 mg/dL and eGFR >60 mL/min/1.73 m(2) to 193 events/1,000 person-years for persons with urine protein excretion ≥300 mg/dL and eGFR <30 mL/min/1.73 m(2).

LIMITATIONS

Results may not be generalizable to female and nonveteran populations.

CONCLUSIONS

In HIV-infected persons, ESRD risk appears attributable to a combination of traditional and HIV-related risk factors for kidney disease. Combining eGFR and proteinuria for chronic kidney disease staging is most effective for stratifying the risk of ESRD.

Relative risk of renal disease among people living with HIV: a systematic review and meta-analysis

Background

Antiretroviral therapy (ART) has substantially decreased mortality and HIV-related morbidity. However, other morbidities appear to be more common among PLHIV than in the general population. This study aimed to estimate the relative risk of renal disease among people living with HIV (PLHIV) compared to the HIV-uninfected population.

Methods

We conducted a systematic review and meta-analysis of relative risks of renal disease among populations of PLHIV reported in studies from the peer-reviewed literature. We searched Medline for relevant journal articles published before September 2010, yielding papers published during or after 2002. We also searched conference proceedings of the International AIDS Society (IAS) and Conference on Retroviruses and Opportunistic Infections (CROI) prior to and including 2010. Eligible studies were observational studies reporting renal disease defined as acute or chronic reduced renal function with glomerular filtration rate less than or equal to 60 ml/min/1.73 m² among HIV-positive adults. Pooled relative risks were calculated for various groupings, including class of ART drugs administered.

Results

The overall relative risk of renal disease was 3.87 (95% CI: 2.85-6.85) among HIV-infected people compared to HIV-uninfected people. The relative risk of renal disease among people with late-stage HIV infection (AIDS) was 3.32 (1.86-5.93) compared to other PLHIV. The relative risk of renal disease among PLHIV who were receiving antiretroviral therapy (ART) was 0.54 (0.29-0.99) compared to treatment-naïve PLHIV; the relative risk of renal disease among PLHIV who were treated with tenofovir was 1.56 (0.83-2.93) compared to PLHIV who were treated with non-tenofovir therapy. The risk of renal disease was also found to significantly increase with age.

Conclusion

PLHIV are at increased risk of renal disease, with greater risk at later stages of infection and at older ages. ART prolongs survival and decreases the risk of renal disease. However, less reduction in renal disease risk occurs for Tenofovir-containing ART than for other regimens.

HIV-associated kidney disease in the context of an aging population

Acute renal failure and chronic kidney disease are more common in HIV-infected patients compared with the general population. Several studies have shown age to be a risk factor for HIV-associated kidney disease. The improved life expectancy of HIV-infected patients as a result of widespread use of antiretroviral therapy has resulted in progressive aging of HIV cohorts in the developed world, and an increased burden of cardiovascular and kidney disease. Consequently, HIV care increasingly needs to incorporate strategies to detect and manage these non-infectious co-morbidities.

Renal issues in HIV infection

Kidney disease remains a prominent complication of HIV disease, despite beneficial effects of antiretroviral therapy on the natural history of HIV-associated nephropathy, and on kidney function in general populations of HIV infected patients. Persons of African descent continue to bear a disproportionate burden of severe kidney disease, as is true for the general population. Recently identified genetic variants in the apolipoprotein L1 gene may contribute to this burden. As is also true for the general population, markers of kidney disease, including microalbuminuria, are sensitive predictors of cardiovascular disease and mortality among persons living with HIV. The emerging experience with kidney transplantation also suggests this to be a viable option in selected patients.

Issues regarding 'immortal time' in the analysis of the treatment effects in observational studies

In observational studies, treatment is often time dependent. Mishandling the time from the beginning of follow-up to treatment initiation can result in bias known as immortal time bias. Nephrology researchers who conduct observational research must be aware of how immortal time bias can be introduced into analyses. We review immortal time bias issues in time-to-event analyses in the biomedical literature and give examples from the nephrology literature. We also use simulations to quantify the bias in different methods of mishandling immortal time; intuitively explain how bias is introduced when immortal time is mishandled; raise issues regarding unadjusted treatment comparison, patient characteristics comparison, and confounder adjustment; and, using data from DaVita Inc., linked with the Centers for Medicare & Medicaid Services end-stage renal disease database, show that the severity of bias and the issues described can occur in actual data analyses of patients with end-stage renal disease. In the simulation examples, mishandling immortal time led to an underestimated hazard ratio (treatment vs. control), thus an overestimated treatment effect, by as much as 96%, and an overestimated hazard ratio by as much as 138%, depending on the distribution of 'survival' time and the method used. Results from the DaVita data were consistent with the simulation. Careful consideration of methodology is needed in observational analyses with time-dependent treatment.

Absence of APOL1 risk variants protects against HIV-associated nephropathy in the Ethiopian population

BACKGROUND

Susceptibility to end-stage kidney disease (ESKD) among HIV-infected Americans of African ancestral heritage has been attributed to APOL1 genetic variation. We determined the frequency of the APOL1 G1 and G2 risk variants together with the prevalence of HIV-associated nephropathy (HIVAN) among individuals of Ethiopian ancestry to determine whether the kidney disease genetic risk is PanAfrican or restricted to West Africa, and can explain the previously reported low risk of HIVAN among Ethiopians.

METHODS

We studied a cohort of 338 HIV-infected individuals of Ethiopian ancestry treated in one Israeli and one Ethiopian center. We sought clinical evidence for HIVAN (serum creatinine >1.4 mg/dl or proteinuria >30 mg/dl in a spot urine sample). Genetic analyses included the genotyping of the APOL1 G1 and G2 variants, and a panel of 33 genomic ancestry-informative markers. Statistical analysis compared clinical and genetic indices for HIV-infected individuals of Ethiopian ancestry and overall Ethiopians to those reported for HIV-infected African-Americans, overall African-Americans, West Africans and non-Africans.

FINDINGS

Three (0.8%) of 338 HIV-infected patients of Ethiopian ancestry showed clinical criteria compatible with renal impairment. Two of these 3 patients also have severe poorly controlled diabetes mellitus. The third nondiabetic patient underwent renal biopsy which ruled out HIVAN. This absence of clinically apparent HIVAN was significantly different from that reported for African-Americans. The APOL1 G1 and G2 risk variants were found, respectively, in 0 and 2 (heterozygote state) of the 338 HIV-infected individuals. Global ancestry and the frequencies of the APOL1 G1 and G2 variants are not statistically different from their frequencies in the general Ethiopian population, but are significantly and dramatically lower than those observed among HIV-infected African-Americans, African-Americans and West Africans.

INTERPRETATION

The coinciding absence of HIVAN and the APOL1 risk variants among HIV-infected individuals of Ethiopian ancestry support a Western rather than Pan-African ancestry risk for ESKD, and can readily explain the lack of HIVAN among individuals of Ethiopian ancestry.

Risk factors of chronic kidney disease in HIV-infected patients

BACKGROUND AND OBJECTIVES

The main aim of this study was determining the risk factors of chronic kidney disease (CKD) in HIV-1-infected patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients were followed from seven large HIV reference centers in France that maintain prospective databases on HIV-1-infected patients. The main outcome was the time to CKD defined as two consecutive measures of estimated GFR ≤60 ml/min per 1.73 m² over ≥3 months. A Cox's model with delayed entry was used to search predictive factors of time to CKD.

RESULTS

From 1993 to 2006, 349 out of 7378 patients were found to have CKD. Of these, 166 had hypertension, 33 had diabetes, and 26 were antiretroviral therapy-naïve. Occurrence of acute kidney injury (hazard ratio [HR] = 2.40) and hypertension (HR = 2.39) were strongly associated with an increased risk of CKD. Patients with a durable level of CD4 count >200 cells/mm³ had a lower risk of CKD (HR = 0.63). Recent exposure to indinavir (HR = 2.03), totenofovir (HR = 1.55), and abacavir (HR = 1.37) were associated with an increased risk of CKD. Past exposure to tenofovir was also associated with an increased risk of CKD (HR = 2.23), and a trend toward significance was observed for past exposure to indinavir (HR = 1.28).

CONCLUSIONS

CKD was not rare in HIV-infected patients and occurs preferentially in HIV-infected patients exposed to certain ARVs, specifically abacavir, indinavir and tenofovir. This requires closer monitoring of renal function in patients exposed to one of these drugs.

Kidney tubular damage in the absence of glomerular defects in HIV-infected patients on highly active antiretroviral therapy

BACKGROUND

The emergence of kidney disease as an important comorbidity among human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) has emphasized the critical importance of early identification of patients at risk for kidney disease. Use of urine as a diagnostic medium may allow the noninvasive detection of incipient nephropathy in these patients.

METHODS

Here, we conducted cross-sectional and 1-year prospective studies of 424 HIV-infected patients on HAART without proteinuria or significant impairment of glomerular function. N-acetyl-β-D-glucosaminidase, γ-glutamyl transpeptidase, β(2)-microglobulin and α(1)-microglobulin were measured as indices of tubular damage, which was diagnosed when urinary concentrations of at least three tubular biomarkers exceeded the reference range. Risk factors associated with tubular damage were examined using multivariate logistic regression analysis.

RESULTS

Tubular damage was identified in 107 patients (25%), who were characterized by advanced age [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01-1.07], high C-reactive protein (OR, 1.96; 95% CI, 1.26-3.14) and coexisting diabetes mellitus (OR, 3.97; 95% CI, 1.44-12.2). The use of tenofovir, the most likely tubulotoxic agent, was not statistically involved in this subclinical tubular damage. The 1-year follow-up study showed that a decrease in estimated glomerular filtration rate (eGFR) and incidence of proteinuria during the period were significantly higher in patients with than without tubular damage.

CONCLUSIONS

A quarter of HIV-infected patients receiving HAART had subclinical tubular damage, which was associated with a near-term decline in eGFR and higher incidence of proteinuria. Periodic monitoring of urinary biomarkers might facilitate the early identification of HAART patients predisposed to significant kidney disease.

Role of the retinoic acid receptor-α in HIV-associated nephropathy

All-trans retinoic acid protects against the development of HIV-associated nephropathy (HIVAN) in HIV-1 transgenic mice (Tg26). In vitro, all-trans retinoic acid inhibits HIV-induced podocyte proliferation and restores podocyte differentiation markers by activating its receptor-α (RARα). Here, we report that Am580, a water-soluble RARα-specific agonist, attenuated proteinuria, glomerosclerosis, and podocyte proliferation, and restored podocyte differentiation markers in kidneys of Tg26 mice. Furthermore, RARα-/- Tg26 mice developed more severe kidney and podocyte injury than did RARα+/- Tg26 mice. Am580 failed to ameliorate kidney injury in RARα-/- Tg26 mice, confirming our hypothesis that Am580 acts through RARα. Although the expression of RARα-target genes was suppressed in the kidneys of Tg26 mice and of patients with HIVAN, the expression of RARα in the kidney was not different between patients with HIVAN and minimal change disease. However, the tissue levels of retinoic acid were reduced in the kidney cortex and isolated glomeruli of Tg26 mice. Consistent with this, the expression of two key enzymes in the retinoic acid synthetic pathway, retinol dehydrogenase type 1 and 9, and the overall enzymatic activity for retinoic acid synthesis were significantly reduced in the glomeruli of Tg26 mice. Thus, a defect in the endogenous synthesis of retinoic acid contributes to loss of the protection by retinoic acid in HIVAN. Hence, RARα agonists may be potential agents for the treatment of HIVAN.

The dual impact of HIV-1 infection and aging on naïve CD4 T-cells: additive and distinct patterns of impairment

HIV-1-infected adults over the age of 50 years progress to AIDS more rapidly than adults in their twenties or thirties. In addition, HIV-1-infected individuals receiving antiretroviral therapy (ART) present with clinical diseases, such as various cancers and liver disease, more commonly seen in older uninfected adults. These observations suggest that HIV-1 infection in older persons can have detrimental immunological effects that are not completely reversed by ART. As naïve T-cells are critically important in responses to neoantigens, we first analyzed two subsets (CD45RA⁺CD31⁺ and CD45RA⁺CD31^-) within the naïve CD4⁺ T-cell compartment in young (20–32 years old) and older (39–58 years old), ART-naïve, HIV-1 seropositive individuals within 1–3 years of infection and in age-matched seronegative controls. HIV-1 infection in the young cohort was associated with lower absolute numbers of, and shorter telomere lengths within, both CD45RA⁺CD31⁺CD4⁺ and CD45RA⁺CD31^-CD4⁺ T-cell subsets in comparison to age-matched seronegative controls, changes that resembled seronegative individuals who were decades older. Longitudinal analysis provided evidence of thymic emigration and reconstitution of CD45RA⁺CD31⁺CD4⁺ T-cells two years post-ART, but minimal reconstitution of the CD45RA⁺CD31^-CD4⁺ subset, which could impair de novo immune responses. For both ART-naïve and ART-treated HIV-1-infected adults, a renewable pool of thymic emigrants is necessary to maintain CD4⁺ T-cell homeostasis. Overall, these results offer a partial explanation both for the faster disease progression of older adults and the observation that viral responders to ART present with clinical diseases associated with older adults.

A simple model for predicting incidence of chronic kidney disease in HIV-infected patients

BACKGROUND

Human immunodeficiency virus (HIV)-infected individuals have concurrent risk factors for chronic kidney disease (CKD), but there are no prediction models to quantify the effect of multiple factors on the development of incident CKD.

METHODS

A 1-year prognostic model was developed using prospective data between January 2008 and March 2009, from a derivation cohort of 623 patients with an estimated glomerular filtration rate (eGFR) exceeding 60 ml/min/1.73 m(2) at baseline. Incident CKD was defined as both an eGFR falling below 60 ml/min/1.73 m(2) and a decrease in eGFR of at least 25% during the period. Continuous variables were divided into categories using the mean value of the whole cohort. Multivariate logistic regression was used to determine baseline categories associated with incident CKD. The model was tested with prospective data between April 2009 and March 2010, from a validation cohort of 534 patients exceeding 60 ml/min/1.73 m(2) at baseline, consisting of part of the derivation cohort and newly enrolled patients. The discriminative ability was evaluated using the area under the receiver operating characteristic (AROC) curve.

RESULTS

Eighteen subjects developed incident CKD (2.9%). In a multivariate logistic regression analysis of the derivation cohort, 5 variables (age, CD4 cell count, diabetes, proteinuria, and eGFR at baseline) were independently associated with the incidence of CKD. The AROC curve was 0.841 (95% CI 0.799-0.894) in the validation cohort.

CONCLUSION

This prediction model may be a useful tool for identifying HIV-infected individuals with a high likelihood of new-onset CKD.

A survey of the management, control, and complications of diabetes mellitus in patients attending a diabetes clinic in Blantyre, Malawi, an area of high HIV prevalence

The aim of this study was to describe the current status of diabetes care in an urban diabetes clinic in Malawi and the prevalence of human immunodeficiency virus (HIV) in this population, investigating possible associations between HIV and diabetes. A systematic prospective survey of patients attending the diabetes clinic at a teaching hospital in Blantyre, Malawi was conducted. Six hundred twenty patients were assessed. Seventy-four percent had glycosylated hemoglobin (HbA1C) > 7.5%. Systolic blood pressure was > 140 mm Hg in 52% of patients. Hypertension was more common in patients with raised creatinine (P < 0.003), retinopathy (P = 0.01), and stroke (P < 0.0002). Microvascular complication rates were high, specifically nephropathy (34.7%), retinopathy (34.7%), and neuropathy (46.4%). HIV seroprevalence was 13.7%. HIV-positive subjects had a lower body mass index (BMI) and lower fasting blood sugar, and they were more likely to have albuminuria (48.0% versus 33.3%; P < 0.05). Control of glycemia and hypertension were poor, and microvascular complications were common. Nephropathy in diabetic patients may be affected by HIV status.

HIV and proteinuria in an injection drug user population

BACKGROUND AND OBJECTIVES

Proteinuria is a major determinant of chronic kidney disease. We aimed to characterize the prevalence and correlates of proteinuria in a cohort of HIV-infected and uninfected injection drug users.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cross-sectional analysis was performed among 902 injection drug users (273 HIV-infected) in the AIDS Linked to the Intravenous Experience cohort. The primary outcome was proteinuria defined as having a urine protein/creatinine concentration ratio >200 mg/g. Poisson regression with robust variance was used to determine prevalence ratios.

RESULTS

Overall, 24.8% of participants had proteinuria; the prevalence was 2.9 times higher among HIV-infected participants (45%) compared with HIV-uninfected participants (16%). In addition, age, health insurance, employment status, hepatitis B and C serostatus, diabetes, and high BP were associated with proteinuria. Neither antiretroviral therapy nor features of illicit drug use history were associated with proteinuria. In multivariate analysis, HIV infection, unemployment, increased age, diabetes, hepatitis C infection, and high BP were significantly associated with a higher prevalence of proteinuria.

CONCLUSIONS

In an aging, predominantly African-American cohort of injection drug users, we found a striking burden of proteinuria that was strongly associated with HIV status. In addition to being a pathway to ESRD, proteinuria is a potent risk factor for cardiovascular morbidity and mortality. Evaluation of aggressive screening and disease-modification strategies in this high-risk population is warranted.

HIV and COPD: impact of risk behaviors and diseases on quality of life

PURPOSE

Smoking worsens quality of life among HIV-infected individuals, but it remains unclear if this association is related simply to smoking or to chronic obstructive pulmonary disease (COPD), the end-organ disease caused by smoking.

METHODS

Using cross-sectional data from the AIDS Linked to the Intravenous Experience study, we determined the independent effects of smoking, HIV and COPD assessed using the Medical Outcome Studies-HIV questionnaire.

RESULTS

Of 973 participants, 287 (29.5%) were HIV infected and 151 (15.5%) had spirometry-defined obstruction. Eight hundred and thirty-four (85.7%) were current smokers with 23.3 mean pack-years history. HIV infection was independently associated with reduced physical and mental health. COPD was associated with a trend toward worse physical health (-1.48 units; 95%CI -3.33 to 0.38; p = 0.12) and was independently associated with worse mental health (-2.43 units; 95%CI -4.22 to -0.64; p < 0.01). After accounting for COPD and other covariates, smoking was not associated with changes in physical or mental health.

CONCLUSIONS

The presence of COPD, rather than smoking, is associated with worse quality of life independent of HIV infection. Diagnosis and management of COPD in former or current smokers with or at risk for HIV may further improve quality of life.

HIV and the Kidney

Direct effects of HIV-1 infection on the kidney combine with immune and genetic factors, comorbidities, coinfections, and medication toxicities to induce a spectrum of kidney disorders in HIV disease. The most dramatic of these, HIV-associated nephropathy (HIVAN), emerges almost exclusively in persons of African descent and is associated with rapid progression to end-stage renal disease in the absence of antiretroviral therapy (ART). ART modifies the natural history of HIVAN, but the renal benefits of ART may not be limited to HIVAN. ART is often under prescribed or incorrectly dosed in persons with kidney disease. Vigilant attention to renal function and an understanding of the complex associations involving the kidneys are necessary for optimal care of these patients.

Prevalence and factors associated with renal dysfunction among HIV-infected patients

Renal dysfunction is an increasingly recognized non-AIDS-defining comorbidity among HIV-infected persons. The role of HIV-related factors in renal dysfunction remains unclear. We performed a cross-sectional study at two military clinics with open access to care to determine the impact of HIV factors, including antiretroviral therapy, on renal function. Renal dysfunction was defined as a glomerular filtration rate (GFR) < 60 mL/min/1.73 m(2). We evaluated 717 HIV patients with a median age of 41 years; 92% were male, 49% Caucasian, and 38% African American; median CD4 count was 515 cells/mm(3) and 73% were receiving highly active antiretroviral therapy (HAART). Twenty-two patients (3%) had renal dysfunction. Factors associated with renal dysfunction in the multivariate logistic analyses included older age (odds ratio [OR] 2.0 per 10 year increase, p = 0.006), lower CD4 nadir (OR 0.6 per 100 cell change, p = 0.02), and duration of tenofovir use (OR 1.5 per year use, p = 0.01). Among persons initiating tenofovir (n = 241), 50% experienced a reduction in GFR (median -10.5 mL/min/1.73 m(2), 95% CI, -8.9 to -13.3) within 2 years. Among tenofovir users, factors associated with a reduction in GFR included female gender (p < 0.001), African American ethnicity (p = 0.003), and lower CD4 nadir (p = 0.002). In summary, renal dysfunction was relatively uncommon among our HIV-infected patients, perhaps due to their young age, lack of comorbidities, or as a result of our definition that did not include proteinuria. Renal dysfunction was associated with duration of tenofovir use. Factors associated with renal loss among tenofovir users included female gender, African American ethnicity, and CD4 nadir <200 cells/mm(3). Consideration for more frequent monitoring of kidney function among these select HIV patients may be warranted.

Renal and urologic emergencies in the HIV-infected patient

Antiretroviral therapy has revolutionized the care of individuals infected with the human immunodeficiency virus (HIV) and has fundamentally altered the scope of the disease. Acute renal failure and chronic kidney disease from medication toxicity and comorbid noninfectious illnesses are just as likely today as end-organ injury from the virus itself. Chronic immunosuppression renders HIV-infected patients vulnerable to any of several unique urological infections not frequently seen in immunocompetent patients. A deeper understanding of renal and urological emergencies in the context of the HIV-infected patient will better prepare the emergency physician to render optimal care to this rapidly expanding and aging patient population.

Cross sectional analysis of respiratory symptoms in an injection drug user cohort: the impact of obstructive lung disease and HIV

Background

Injection drug use is associated with an increased risk of human immunodeficiency virus (HIV) infection and with obstructive lung diseases (OLD). Understanding how HIV and OLD may impact respiratory symptoms among injection drug users (IDUs) is important to adequately care for this high-risk population. We characterized the independent and joint effects of HIV and OLD on respiratory symptoms of a cohort of inner-city IDUs.

Methods

Demographics, risk behavior and spirometric measurements were collected from a cross-sectional analysis of the Acquired Immunodeficiency Syndrome Link to the IntraVenous Experience study, an observational cohort of IDUs followed in Baltimore, MD since 1988. Participants completed a modified American Thoracic Society respiratory questionnaire and the Medical Research Council (MRC) dyspnea score to assess respiratory symptoms of cough, phlegm, wheezing and dyspnea.

Results

Of 974 participants, 835 (86%) were current smokers and 288 (29.6%) were HIV-infected. The prevalence of OLD (FEV1/FVC ≤ 0.70) was 15.5%, and did not differ by HIV status. OLD, but not HIV, was associated with increased frequency of reported respiratory symptoms. There was a combined effect of OLD and HIV on worsening of MRC scores. OLD and HIV were independently associated with an increased odds of reporting an MRC ≥ 2 (OR 1.83 [95%CI 1.23-2.73] and 1.50 [95%CI 1.08-2.09], respectively). COPD, but not HIV, was independently associated with reporting an MRC ≥ 3 (OR 2.25 [95%CI 1.43-3.54] and 1.29 [95%CI 0.87-1.91], respectively).

Conclusions

While HIV does not worsen cough, phlegm or wheezing, HIV significantly increases moderate but not severe dyspnea in individuals of similar OLD status. Incorporating the MRC score into routine evaluation of IDUs at risk for OLD and HIV provides better assessment than cough, phlegm and wheezing alone.

[Diagnosis, treatment and prevention of renal diseases in HIV infected patients. Recommendations of the Spanish AIDS Study Group/National AIDS Plan]

The incidence of opportunistic infections and tumours in HIV-infected patients has sharply declined in the HAART era. At the same time there has been a growing increase of other diseases not directly linked to immunodeficiency. Renal diseases are an increasing cause of morbidity and mortality among HIV-infected patients. In the general population, chronic renal failure has considerable multiorgan repercussions that have particular implications in patients with HIV infection. The detection of occult or subclinical chronic kidney disease is crucial since effective measures for delaying progression exist. Furthermore, the deterioration in glomerular filtration should prompt clinicians to adjust doses of some antiretroviral agents and other drugs used for treating associated comorbidities. Suppression of viral replication, strict control of blood pressure, dyslipidemia and diabetes mellitus, and avoidance of nephrotoxic drugs in certain patients are fundamental components of programs aimed to prevent renal damage and delaying progression of chronic kidney disease in patients with HIV. Renal transplantation and dialysis have also special implications in HIV-infected patients. In this article, we summarise the updated clinical practice guidelines for the evaluation, management and prevention of renal diseases in HIV-infected patients from a panel of experts in HIV and nephrologists on behalf of the Spanish AIDS Study Group (GESIDA) and the National AIDS Plan.

Hepatitis C and the risk of kidney disease and mortality in veterans with HIV

OBJECTIVES

To examine the effect of hepatitis C virus (HCV) on the prevalence of chronic kidney disease (CKD) among veterans with HIV and to evaluate independent associations of HCV and CKD with mortality.

METHODS

We studied a national cohort of HIV-infected patients receiving care through the Veterans Healthcare Administration from 1998 to 2004. CKD was defined as an estimated glomerular filtration rate [eGFR (mL/min/1.73 m2)] < 60. Poisson regression was used to assess relationships between CKD, HCV, and mortality.

RESULTS

Among 23,155 HIV-infected veterans, 12% had CKD. Forty percent of the cohort was coinfected with HCV, and a higher proportion of coinfected subjects had CKD compared with monoinfected subjects (14% vs 11%, P < 0.001). During the median follow-up of 7.6 years, 37% of subjects died and a graduated increase in adjusted mortality rates occurred with lower levels of eGFR (P < 0.001). Adjusted mortality rates were consistently higher in HCV-coinfected subjects across all levels of eGFR (P < 0.001). HCV was independently associated with increased mortality (incidence rate ratio 1.23, 95% confidence interval 1.17-1.29).

CONCLUSIONS

CKD is prevalent in HIV-infected veterans and associated with substantially higher mortality. Compared with their monoinfected counterparts, veterans coinfected with HCV have significantly higher rates of CKD and mortality.

The nephrotoxic effects of HAART

With significant reductions in mortality and risk of progression to AIDS in the era of highly active antiretroviral therapy (HAART), complications of long-standing HIV infection and treatment have become increasingly important. Such complications include the nephrotoxic effects of HAART, which are the subject of this Review. The most common nephrotoxic effects associated with HAART include crystal-induced obstruction secondary to use of protease inhibitors (mainly indinavir and atazanavir), and proximal tubule damage related to the nucleotide analog reverse transcriptase inhibitor tenofovir. Acute kidney injury (AKI) can occur following tenofovir-induced tubule dysfunction or as a result of severe mitochondrial dysfunction and lactic acidosis induced by nucleoside reverse transcriptase inhibitors. The potential insidious long-term renal toxicity of antiretroviral treatment is probably underappreciated in patients with HIV: a proportion of patients with treatment-related AKI did not recover their baseline renal function at 2-year follow-up, suggesting the possibility of permanent renal damage. Finally, nonspecific metabolic complications might increase the risk of vascular chronic kidney disease in patients on HAART. However, given the benefits of HAART, fear of nephrotoxic effects is never a valid reason to withhold antiretroviral therapy. Identification of patients with pre-existing chronic kidney disease, who are at increased risk of renal damage, enables appropriate dose modification, close monitoring, and avoidance or cautious use of potentially nephrotoxic medications.

Diagnosis and natural history of HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) is a largely distinctive phenotype induced by HIV-1 infection and is the most recognized and detrimental kidney disease in HIV-infected patients. Host and viral characteristics have been implicated in the pathogenesis of HIVAN that may explain its exclusive predilection to patients of African descent. In untreated patients, the disorder is clinically manifested by an acute decline in kidney function, most often in conjunction with high-grade proteinuria and uncontrolled HIV-1 infection. Histologically, proliferating glomerular epithelial cells are the prominent feature of the disease. Data have evolved over the past decade suggesting that highly active antiretroviral therapy (HAART) can change the natural history of HIVAN, not only by preventing its development but also by halting its progression once developed. Consequently, with the widespread use of HAART, the prevalence of HIVAN is declining in Western countries. In contrast, the epidemiology of the disease is not well defined in the poorest areas in the world, which bear a disproportionate share of the HIV-1 epidemic's burden. Corticosteroids and inhibition of the renin-angiotensin axis are recommended as adjunctive agents in treating patients with established HIVAN and are potentially helpful in delaying the need for renal replacement therapy. However, the long-term value and potential risks of using corticosteroids in this population are unclear.

Gene-gene and gene-environment interactions in HIV-associated nephropathy: A focus on the MYH9 nephropathy susceptibility gene

HIV-associated nephropathy (HIVAN) is a leading cause of ESRD in African Americans. The HIV-1 virus infects podocytes, cells integral to formation of the glomerular filtration barrier, often leading to focal segmental glomerulosclerosis. HIVAN is typically a complication of late-stage HIV infection, associated with low CD4 cell counts and elevated serum HIV RNA levels. Highly active antiretroviral therapy is partially protective and has altered the natural history of HIV-associated kidney disease. Nonetheless, HIVAN remains an important public health concern among HIV-infected African Americans. Although polymorphisms in the MYH9 gene on chromosome 22 are strongly associated with HIVAN, as well as with idiopathic focal segmental glomerulosclerosis and global glomerulosclerosis (historically labeled "hypertensive nephrosclerosis"), the majority of HIV-infected patients who are genetically at risk from MYH9 do not appear to develop severe kidney disease. Therefore, we postulate that additional environmental exposures and/or inherited factors are necessary to initiate human HIVAN. Gene-environment interactions have also been proposed as necessary for the initiation of HIVAN in murine models. It is important that these novel risk factors be identified because prevention of environmental exposures and targeting of additional gene products may reduce the risk for HIVAN, even among those harboring 2 risk alleles in MYH9.

Clinical epidemiology of HIV-associated end-stage renal failure in the UK

OBJECTIVE

To describe the clinical epidemiology of HIV-associated end-stage renal failure (HIV/ESRF) from 1998 to 2007 in the United Kingdom.

DESIGN

Observational cohort study.

SETTING

Seven leading HIV centres and affiliated renal clinics in the United Kingdom.

PARTICIPANTS

A total of 21 951 patients in whom renal function was measured.

MAIN OUTCOME MEASURE

Development of end-stage renal failure (ESRF) as defined by initiation of permanent renal replacement therapy (pRRT).

RESULTS

Sixty-eight (0.31%) patients had HIV/ESRF, 44 (64.7%) of whom were black. The prevalence of ESRF in black patients increased over time from 0.26% in 1998-1999 to 0.92% in 2006-2007 (P for trend = 0.001). Overall 5-year survival from starting pRRT was 70.3%, and significantly better for black patients compared to those of other ethnicities (85.2 vs. 43.4%, P = 0.001). In multivariable analysis, black ethnicity was associated with a higher risk of ESRF [HR 6.93, 95% confidence interval (CI) 3.56, 13.48], whereas a higher current CD4 cell count was associated with reduced risk (HR: 0.83, 95% CI 0.76, 0.95) per 50 cells higher). No association was seen between current viral load or current highly active antiretroviral therapy (HAART) status and ESRF. On the basis of these observations, we estimate that 231 HIV-infected patients required pRRT in the United Kingdom in 2007, and an HIV prevalence of 0.51% among the United Kingdom pRRT recipients in that year.

CONCLUSION

The prevalence of HIV/ESRF increased during the HAART era to reach nearly 1% in black patients, in whom favourable survival rates were observed. Earlier HIV diagnosis will be an important strategy to stem the rising trend of HIV/ESRF.

HIV viremia and changes in kidney function

OBJECTIVE

To evaluate the effect of HIV infection on longitudinal changes in kidney function and to identify independent predictors of kidney function changes in HIV-infected individuals.

DESIGN

A prospective cohort.

METHODS

Cystatin C was measured at baseline and at the 5-year follow-up visit of the Study of Fat Redistribution and Metabolic Change in HIV infection in 554 HIV-infected participants and 230 controls. Control participants were obtained from the Coronary Artery Risk Development in Young Adults study. Glomerular filtration rate (eGFRcys) was estimated using the formula 76.7 x cysC(-1.19).

RESULTS

Compared with controls, HIV-infected participants had a greater proportion of clinical decliners (annual decrease in eGFRcys > 3 ml/min per 1.73 m2; 18 versus 13%, P = 0.002) and clinical improvers (annual increase in eGFRcys > 3 ml/min per 1.73 m2; 26 versus 6%, P < 0.0001). After multivariable adjustment, HIV infection was associated with higher odds of both clinical decline (odds ratio 2.2; 95% confidence interval 1.3, 3.9, P = 0.004) and clinical improvement (odds ratio 7.3; 95% confidence interval 3.9, 13.6, P < or = 0.0001). Among HIV-infected participants, a decrease in HIV viral load during follow-up was independently associated with clinical improvement; conversely, higher baseline and an increase in viral load during follow-up were associated with clinical decline. No individual antiretroviral drug or drug class appeared to be substantially associated with clinical decline or improvement.

CONCLUSION

Compared with controls, HIV-infected persons were more likely both to have clinical decline and clinical improvement in kidney function during 5 years of follow-up. The extent of viremic control had a strong association with longitudinal changes in kidney function.

Cystatin C: current position and future prospects

Cystatin C is a low-molecular-weight protein which has been proposed as a marker of renal function that could replace creatinine. Indeed, the concentration of cystatin C is mainly determined by glomerular filtration and is particularly of interest in clinical settings where the relationship between creatinine production and muscle mass impairs the clinical performance of creatinine. Since the last decade, numerous studies have evaluated its potential use in measuring renal function in various populations. More recently, other potential developments for its clinical use have emerged. This review summarises current knowledge about the physiology of cystatin C and about its use as a renal marker, either alone or in equations developed to estimate the glomerular filtration rate. This paper also reviews recent data about the other applications of cystatin C, particularly in cardiology, oncology and clinical pharmacology.

End-stage renal disease and kidney transplant in HIV-infected patients

Chronic kidney and end-stage renal disease are important complications of HIV disease and treatment. African Americans with HIV infection are at significantly increased risk for development of chronic kidney disease and for progression to end-stage renal disease. Survival of HIV-positive patients on dialysis has improved dramatically since the introduction of combination antiretroviral therapy, with hemodialysis and peritoneal dialysis appearing to offer similar survival. Renal transplant has been shown to be successful in HIV-positive patients and emerging data suggest a survival benefit over remaining on dialysis, despite data indicating an increased incidence of acute rejection. Immunosuppression dosing is complicated by interactions with antiretroviral therapy, and drug levels must be followed closely. Experience to date suggests that HIV-positive transplant recipients are best cared for in academic institutions with multi-disciplinary teams devoted to their care.

The spectrum of kidney disease in patients with AIDS in the era of antiretroviral therapy

With prolonged survival and aging of the HIV-infected population in the era of antiretroviral therapy, biopsy series have found a broad spectrum of HIV-related and co-morbid kidney disease in these patients. Our study describes the variety of renal pathology found in a prospective cohort of antiretroviral-experienced patients (the Manhattan HIV Brain Bank) who had consented to postmortem organ donation. Nearly one-third of 89 kidney tissue donors had chronic kidney disease, and evidence of some renal pathology was found in 75. The most common diagnoses were arterionephrosclerosis, HIV-associated nephropathy and glomerulonephritis. Other diagnoses included pyelonephritis, interstitial nephritis, diabetic nephropathy, fungal infection and amyloidosis. Excluding 2 instances of acute tubular necrosis, slightly over one-third of the cases would have been predicted using current diagnostic criteria for chronic kidney disease. Based on semi-quantitative analysis of stored specimens, pre-mortem microalbuminuria testing could have identified an additional 12 cases. Future studies are needed to evaluate the cost-effectiveness of more sensitive methods for defining chronic kidney disease, in order to identify HIV-infected patients with early kidney disease who may benefit from antiretroviral therapy and other interventions known to delay disease progression and prevent complications.