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.
Publisher
University of Nairobi