Comparison of Clinical Characteristics and One Year Outcomes Among Hiv Positive and Hiv Negative Patients on Maintenance Haemodialysis at the Kenyatta National Hospital and Nairobi Hospital Renal Units

Abstract

Background HIV remains a leading cause of mortality in Kenya. Additionally, prevalence of chronic kidney disease (CKD) is on the rise both globally and locally. HIV is a known risk factor for chronic kidney disease, and with greater life expectancy among HIV positive patients, the number of patients with both HIV and chronic kidney disease is predicted to rise. Little is known about the outcomes including mortality rates of HIV positive patients on haemodialysis compared to their HIV negative counterparts in our region. Further, there is a paucity of local published data regarding the prevalence of HIV among patients undergoing maintenance haemodialysis. Aims This study’s aim was to determine the documented prevalence of HIV among patients on haemodialysis at the Kenyatta National Hospital and Nairobi Hospital Renal Units between 1st January 2010 and 31st December 2019. It further compared selected clinical characteristics, one year mortality and loss to follow up rates among HIV positive patients on haemodialysis during this period compared to their HIV negative counterparts. Methods This was a retrospective cohort study, involving chart review of patients on maintenance haemodialysis at the Kenyatta National Hospital and Nairobi Hospital Renal Units between 1st January 2010 and 31st December 2019. Outcomes (mortality, loss to follow up) at one year since initiation of haemodialysis in the Units were compared between HIV positive patients on haemodialysis versus HIV negative patients matched by age, sex, year of dialysis initiation and dialysis centre. Rates of documented vascular access-related infection were also compared. Statistical analysis Sociodemographic variables were presented as means (± standard deviation) for continuous variables and proportions for categorical variables. Chi square test was used to compare proportion of haemodialysis patients with the outcomes of interest (mortality, loss to follow up at one year), comparing HIV positive patients with their HIV negative counterparts. Time to mortality or loss to follow up for each group was derived from Kaplan-Meier plots. Statistical significance was defined at a p value of less than 0.05. 11 Results HIV prevalence among 565 patients on maintenance haemodialysis between 2010 and 2019 at the two centres was 11.9%. Male:female ratio was 1.9:1, with a mean age of 50.0 [±12.7] years and 50.2[±13.3] years among HIV positive and HIV negative patients respectively. All 67 HIV positive and 201 HIV negative patients (1:3 ratio) matched by age, sex, year of dialysis initiation and dialysis centre were included in the final analysis. Median duration on haemodialysis was significantly shorter among HIV positive patients at 15 months [IQR 5-36] compared to 24 months [IQR 12-36] among HIV negative patients. HIV positive patients were less likely to utilize an arteriovenous fistula for dialysis (OR 0.4[95% CI: 0.2-0.9], p=0.019), had a twofold higher risk of vascular access-related infections (OR 2.0[95% CI: 1.1-3.6]. p=0.03), and a 5.6 fold higher risk of tuberculosis compared to HIV negative patients (OR 5.6[95% CI: 1.0-29.9], p=0.039). Mean haemoglobin, serum calcium and albumin levels were also significantly lower among HIV positive patients compared to their HIV negative counterparts (mean haemoglobin 7.7g/dl [±1.1] versus 8.4g/dl [±1.4] respectively, p=0.001; mean serum calcium 1.8mmol/l [±0.3] versus 2.0mmol/l [±0.3] respectively, p<0.001; mean albumin 31.0g/l [±5.1] versus 33.0 [±5.5] respectively, p=0.007). HIV positive patients were also five times more likely to have received a blood transfusion (OR 5.4[95% CI: 2.4-12.5], p<0.001). There was a trend towards higher mortality at one year among HIV positive patients (22.4%) compared to HIV negative patients (13.4%), p=0.053. Time to mortality at one year was significantly shorter among HIV positive patients (log rank p value from the Kaplan Meier estimates=0.038). HIV positive patients were also twice as likely to be lost to follow up (OR 2.9 [95% CI: 1.1-7.9], p=0.034). Conclusion Prevalence of HIV among patients on maintenance haemodialysis is higher than in the general population at 11.9%. There is a higher risk of vascular access-related infections, tuberculosis, lower haemoglobin, lower albumin and lower serum calcium levels among HIV positive patients on maintenance haemodialysis compared to HIV negative patients. There was a trend towards higher mortality at one year among HIV positive patients, who also had a significantly shorter time to mortality, as well as higher rates of loss to follow up compared to HIV negative patients.