Kidney disease in patients with HIV infection and AIDS

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.

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.

Development of diagnostic criteria for serious non-AIDS events in HIV clinical trials

PURPOSE

Serious non-AIDS (SNA) diseases are important causes of morbidity and mortality in the HAART era. We describe development of standard criteria for 12 SNA events for Endpoint Review Committee (ERC) use in START, a multicenter international HIV clinical trial.

METHODS

SNA definitions were developed based upon the following: (1) criteria from a previous trial (SMART), (2) review of published literature, (3) an iterative consultation and review process with the ERC and other content experts, and (4) evaluation of draft SNA criteria using retrospectively collected reports in another trial (ESPRIT).

RESULTS

Final criteria are presented for acute myocardial infarction, congestive heart failure, coronary artery disease requiring drug treatment, coronary revascularization, decompensated liver disease, deep vein thrombosis, diabetes mellitus, end-stage renal disease, non-AIDS cancer, peripheral arterial disease, pulmonary embolism, and stroke. Of 563 potential SNA events reported in ESPRIT and reviewed by an ERC, 72% met "confirmed" and 13% "probable" criteria. Twenty-eight percent of cases initially reviewed by the ERC required follow-up discussion (adjudication) before a final decision was reached.

CONCLUSION

HIV clinical trials that include SNA diseases as clinical outcomes should have standardized SNA definitions to optimize event reporting and validation and should have review by an experienced ERC with opportunities for adjudication.

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 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.

Integrating HIV-related evidence-based renal care guidelines into adult HIV clinics

The purpose of this evidence-based practice (EBP) project was to implement research-based, clinic-specific renal care guidelines into two adult HIV clinics. The two main components of the project included (a) implementation of clinic-specific renal care guidelines and (b) initiation of renal and general health patient education by clinic support staff. Overall, statistically significant improvement was shown postguideline implementation in proportion of urinalyses (UA) (p = .01) and estimated glomerular filtration rates (eGFR) (p = .002) completion for patients during initial clinic visits and for those requiring yearly (UA p < .001, eGFR p < .001) or twice-yearly (UA p < .001, eGFR p < .001) renal testing. The rate of renal health education provided to patients by nurses was 60.7%. Results suggest that advanced practice nurse-led EBP change implementation can result in better renal care in outpatient HIV care settings. The process described could be used to implement EBP in other clinic sites.

Renal disease in AIDS: it is not always HIVAN

Human immunodeficiency virus (HIV) infection can cause a broad spectrum of clinical manifestations, ranging from an asymptomatic carrier state to severe immunodeficiency. The most common renal lesion, HIV-associated nephropathy (HIVAN), is a sclerosing glomerulopathy. However, potentially reversible causes of renal disease in HIV-infected patients should also be considered. We describe two cases of patients with acquired immune-deficiency syndrome (AIDS) who presented with rapidly progressive renal failure but were found to have reversible etiologies. The first case was found to have syphilis and the second, disseminated histoplasmosis; their renal injury resolved after initiation of a third-generation cephalosporin antibiotic and amphotericin B, respectively.

The treatment of HIV-associated nephropathy

Antiretroviral therapy (ART) preserves kidney function in patients with human immunodeficiency virus (HIV)-associated nephropathy (HIVAN). Emerging data also document substantial renal benefits of ART in the general HIV-infected population, which is associated in part with suppression of HIV-1 viral replication. The extent to which the response to ART differs in persons with HIVAN compared with those with other HIV-associated kidney disorders is unknown. Beneficial effects of corticosteroids and angiotensin-converting enzyme inhibitors on kidney function also are suggested by retrospective cohort studies and uncontrolled trials of patients with HIVAN. Underexposure to ART or inadequate ART dosing in HIV-infected patients with CKD may curtail the optimal benefits that may be derived from this therapy.

Lipid abnormalities in a never-treated HIV-1 subtype C-infected African population

Dyslipidemia has been documented worldwide among human immunodeficiency virus-infected (HIV) individuals and these changes are reminiscent of the metabolic syndrome (MetS). In South Africa, with the highest number of HIV infections worldwide, HIV-1 subtype C is prevalent, while HIV-1 subtype B (genetically different from C) prevails in Europe and the United States. We aimed to evaluate if HIV infection (subtype C) is associated with dyslipidemia, inflammation and the occurrence of the MetS in Africans. Three hundred newly diagnosed HIV-infected participants were compared to 300 age, gender, body mass index and locality matched uninfected controls. MetS was defined according to the Adult Treatment Panel III (ATP III) and International Diabetes Federation (IDF) criteria. The HIV-infected group showed lower high density lipoprotein cholesterol (1.23 vs. 1.70 mmol/L) and low density lipoprotein cholesterol (2.60 vs. 2.80 mmol/L) and higher triglycerides (1.29 vs. 1.15 mmol/L), C-reactive protein (3.31 vs. 2.13 mg/L) and interleukin 6 (4.70 vs. 3.72 pg/L) levels compared to the uninfected group. No difference in the prevalence of the MetS was seen between the two groups (ATP III, 15.2 vs. 11.5%; IDF, 21.1 vs. 22.6%). This study shows that HIV-1 subtype C is associated with dyslipidemia, but not with a higher incidence of MetS in never antiretroviral-treated HIV-infected Africans.

Human immunodeficiency virus in an aging population, a complication of success

The proportion of human immunodeficiency virus (HIV)-infected patients aged 50 and older has greatly increased since the beginning of the epidemic, particularly since 1996, when combination antiretroviral therapy became available. By 2015, 50% of HIV-infected individuals in the United States are likely to be aged 50 and older. The rate of progression of untreated HIV disease, response to therapy, and complicating effects of comorbidities differ in older and younger patients. Older untreated patients with HIV demonstrate faster rates of CD4(+) cell loss and more rapid progression to acquired immunodeficiency syndrome (AIDS) and death than younger individuals. Synergistic deleterious effects of chronic immune activation on the course of HIV infection with the immune senescence of aging may promote this accelerated course. Despite the increasing prevalence in older patients and cost-effectiveness analyses that favor HIV testing, older patients are less likely to be routinely evaluated for HIV infection. Consequently, when diagnosed, older patients have more-advanced disease than do younger patients and, upon presentation with AIDS-defining conditions, are less likely to receive timely appropriate therapy. The treatment of older HIV-infected patients is complicated by preexisting comorbid conditions, including cardiovascular, hepatic, and metabolic complications, which in turn may be exacerbated by the effects of HIV infection per se, modest immunodeficiency (i.e., at CD4(+) counts >350 cells/microL), and the metabolic and other adverse effects of combination antiretroviral therapy. Nevertheless, older patients derive substantial benefit from combination antiretroviral therapy despite having less of an immunological response than expected given their adherence to therapy and excellent virological responses.

Renal function in patients with preexisting renal disease receiving tenofovir-containing highly active antiretroviral therapy in the HIV outpatient study

Few data exist on the safety of tenofovir (TDF) in HIV-infected patients with preexisting renal dysfunction. We report 12-month changes in renal profiles among 19 such patients (6 patients with history of and 13 patients with current renal disease) in the HIV Outpatient Study (HOPS) who initiated TDF-containing highly active antiretroviral therapy (HAART) during 2001-2005 with TDF dosed mostly at 300 mg once daily. At baseline, the median estimated glomerular filtration rate (GFR) was 49 mL/min/1.73 m(2) and the median CD4(+) cell count was 322 cells/mm(3). Patients had a median 12-month change in estimated creatinine clearance from baseline of -0.3 mL/min (range, -32.2 to +23.6) and the median change in GFR of -0.1 mL/min/1.73 m(2) (range, -49.8 to +29.5). We observed confirmed worsening of kidney disease stage in 5 of the 19 patients during follow-up. TDF use can be considered in patients with preexisting or current renal dysfunction who have limited antiretroviral treatment options, require TDF for fully active antiretroviral regimen, and can be closely monitored for incident worsening of renal function.