Incidence and risk factors for the development of indinavir-associated renal complications

Objectives: To describe the incidence and risk factors for the development of indinavir-associated renal complications (IRC), and subsequent clinical outcome. Patients and methods: This was a retrospective cohort study based on two la rge HIV centres in London. Eligible patients received indinavir for at leas t 1 week between 1 December 1995 and 28 February 1999. Development of IRC w as ascertained by case-note review. Multivariate logistic regression and Co x Proportional Hazard's model analysis were used to determine independent r isk factors for the development of IRC. Results: 781 patients were eligible. Median CD4 count and viral load at ind inavir initiation were 117 x 10(6) cells/L and 47 332 copies/mL, respective ly. Median indinavir exposure was 53 weeks (IQR: 20-83). Many patients rece ived other potentially nephrotoxic drugs during indinavir treatment: co-tri moxazole (46%), aciclovir (33%) or both (20%). Overall IRC incidence was 7. 3% (6.7 per 100 person-years indinavir exposure). Cases presented with loin pain (58%), renal colic (42%) or dysuria (19%). Identified precipitating e vents (26%) included fluid depletion or altered indinavir regimen. In the m ajority of cases indinavir therapy was continued and there was no progressi ve rise in creatinine levels. In the multivariate analysis, for indinavir t reatment > 74 weeks there was a reduced risk of developing IRC (OR = 0.23,9 5% CI 0.09-0.57, P = 0.001). Concomitant aciclovir increased the IRC risk ( OR = 1.99,95% CI 1.14-3.51, P = 0.016). Factors not associated with outcome were age, gender, ethnicity, baseline CD4 count and viral load, concomitan t co-trimoxazole, or use of specific antiretrovirals. Conclusion: An overall IRC incidence of 7.3% was identified. Concomitant ac iclovir doubled the risk of IRC and we therefore recommend careful monitori ng when prescribing aciclovir with indinavir. A precipitating event was ide ntified in 26% of IRC cases, many of which could have been avoided.