Chronic kidney disease in rheumatoid arthritis at Kenyatta National Hospital

Abstract

Background Rheumatoid arthritis is a global health problem with an increase in prevalence especially in SubSaharan Africa. The disease has high morbidity and mortality even with recent improvements in disease management. Majority of those with rheumatoid arthritis die from cardiovascular diseases and this risk is augmented in the presence of chronic kidney disease. Objectives To determine the prevalence and stage of chronic kidney disease in patients with rheumatoid arthritis on follow up at the rheumatology outpatient clinic at Kenyatta National hospital. To determine the association of renal dysfunction with: duration of rheumatoid arthritis, disease activity of rheumatoid arthritis and treatment used for rheumatoid arthritis. Methods A total of 104 participants with a diagnosis of rheumatoid arthritis were recruited from the Kenyatta National Hospital rheumatology outpatient clinic. In this cross-sectional survey, continuous sampling was applied. Participants had to be of age 18 or more years. Data was collected over a ten week period. Patients’ records were examined for medication used and duration of illness. Demographic data and medical history were collected by the use of prestructured questionnaires and a brief physical exam undertaken. This was followed by blood collection for assessment of creatinine levels and ESR as well as a urine sample for urinalysis. Serum creatinine was analysed by an automated biochemistry machine. Urinalysis was performed via urinary dipstick and ESR by the Wintrobe method. Analysis Data was presented using tables, pie charts and bar charts. Continuous data was summarized using measures of central tendency (means, medians, mode and standard deviations). Dependent variables were analysed for correlation with a p value of 0.05 or less considered significant. Chronic kidney disease was correlated with: disease duration using the Kruskall Wallis test, disease activity using the ANOVA test and treatment modality using the Chi-square test. Outcomes A total of 104 patients were recruited over a ten week period. Out of these, 93 (89.4%) were female with a female to male ratio of 9:1. Mean age of patients was 48.7(±15.6) years. Majority of the patients (86.5%) were on at least one DMARD. Methotrexate was the commonest DMARD used. Others were leflunomide, sulfasalazine and hydroxychloroquine. None of our patients was on a biologic agent. Use of NSAIDs and /or prednisone was very frequent (88.5%). Median duration of disease since time of diagnosis was 4 years. Majority of patients (60%) had active disease. We found the prevalence of chronic kidney disease to be 28.7% (95% CI 19.137.2%) based on estimated glomerular filtration rate using the Cockroft-Gault formula. Majority (50%) of which was stage 3a disease and none with end stage renal disease. We found no patients with proteinuria using a urinary dipstick. Conclusion Although we did not find any proteinuria in our study population, prevalence of chronic kidney disease based on estimated glomerular filtration rate was high. The majority of chronic kidney disease was in the early stages. Use of urine strips alone is not an adequate screening tool in this population.