Prevalence of and factors associated with chronic kidney disease in osteoarthritis patients at Kenyatta National Hospital

Abstract

Background: Chronic Kidney Disease (CKD) is a global health problem with an increase in prevalence especially in Sub-Saharan Africa (SSA). It has a high morbidity and mortality. CKD and osteoarthritis (OA) are related as they both increase with age and are associated with comorbidities e.g. hypertension, obesity etc. However, there is limited evidence on the prevalence and associated risk factors of CKD among OA patients.
Objective: To assess the prevalence and factors associated with CKD in OA patients attending Rheumatology and Orthopaedic clinics at Kenyatta National Hospital.
Design: A hospital-based descriptive cross-sectional study.
Methods: The study was conducted between November 2019 and January 2020 involving patients aged 18 years and above; being followed up in the rheumatology and orthopaedic clinics at Kenyatta National Hospital with a diagnosis of knee, hip, spine and hand osteoarthritis based on the American College of Rheumatology criteria. Chronic kidney disease was defined as an eGFR of less than or equal to 60 ml/min/1.73m2 and/or
proteinuria of 30 mg/dl detected on urinary dipstick for three months or more. Descriptive statistics were used to describe the participants. Association between participants’ characteristics and CKD prevalence were assessed using chi-square and factors associated with CKD among OA patients using bivariate and multivariable logistic regressions.
Results: The overall prevalence of CKD among patients with osteoarthritis was 61.9% (56.4–66.3) as per eGFR using Cockrauft Gault (CG). Most were in CKD stage 3 at 59.2% with 45.5% in G3a and 13.7% in G3b. One point one percent were in stage 1, 38.3% in stage 2 and 1.4% were in CKD stage 4 and 5. Only 12.1% of the respondents had persistent proteinuria and thus most of the patients had low and moderate risk for CKD progression at
38% and 38.2% respectively. Only 12.1% and 11.6% had high and very high risk for CKD progression. The CKD prevalence increased with age, being highest among older adults (65+ years). The prevalence was higher among men than women (65.9%, 95% CI: 54.7–75.5 vs. 60.2%, 95% CI: 54.4–65.7). The factors associated with CKD in OA were old age, hypertension and poor and fair self-rated health which increased the odds of CKD while moderate physical activity, overweight/obesity and use of more than one medication (NSAID/ACEI/ARB) reduced the odds of CKD.
Conclusion: This study provides evidence that osteoarthritis is associated with a high prevalence of CKD. However, most of the patients are  asymptomatic and in low and moderate risk category based on Kidney Disease Improving Global Outcomes (KDIGO) nomenclature. Osteoarthritis patients should be considered a high-risk group for chronic kidney disease given their older age, chronic use of NSAIDs and high prevalence of
comorbidities e.g. hypertension, overweight/obesity which are known risk factors for CKD. Screening for CKD in OA patients should therefore be done routinely as is the case in other high risk groups e.g. diabetes.

Key words: Chronic Kidney Disease (CKD), Osteoarthritis (OA), Cockrauft-Gault (CG), Estimated Glomerular Filtration Rate (eGFR), Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Angiotensin-Converting Enzyme Inhibitors (ACEI), Angiotensin Receptor Blockers (ARB)