Kidney Function in Frequent Users of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Background: Non-steroidal anti-inflammatory drugs (NSAIDs) are used for managing painful conditions. They are available as cheap, over-the-counter drugs, and commonly abused. NSAIDs inhibit prostaglandins (PGs) actions on the kidneys and can cause kidney disease and hypertension, especially when used in excess doses, for prolonged period or in stressed states. Methods: The descriptive study was carried at the Orthopaedic and Family Medicine units of the Federal Medical Centre, Abeokuta. Two hundred respondents participated in the study. One hundred frequent users of NSAIDs (with daily use for ≥ 4 weeks) and age and sex-matched controls with no known risk for kidney disease and had consented were consecutively recruited. Data were entered from history, examination and investigations (urinalysis, serum electrolyte, kidney scan and biopsy). Cases with estimated glomerular filtration rate (eGFR) < 60 mls/min/1.73 m2) and dip strip proteinuria ≥ 1+ had kidney biopsy. Statistical analysis was with SPSS 21 software. Student t-test and Chi-square tests were used to compare means and proportions respectively. Pearson’s correlation test was used to determine the strength of association between independent risk factors and kidney dysfunction (KD). Results: Two hundred respondents participated in the study. Fifty one (51) females and Forty nine (49) males were recruited as cases and controls respectively. Thirteen (13) females had KD compared to 9 males, (P = 0.02). The mean age of cases with KD (63.04 yrs ± 4.21) was statistically higher than those without KD (P = 0.01). Majority of the cases were in the working population (30 - 59 yrs). Twenty two (22) frequent NSAIDs users had kidney dysfunction (KD) while six (6%) controls had KD. The proportion of subjects that used herbal medicines was higher in cases with KD than in cases without KD as well as in the controls respectively (P = 0.01). The mean kidney length and cortical thickness were significantly lower in cases with KD than in cases without KD, (P = 0.03) and (P = 0.017) respectively. The independent predictors of KD were increasing age, use of herbal remedies and duration of drug use. Conclusion: The prevalence of KD among frequent NSAIDs users was 22%, higher than controls. Risk factors identified include increasing age, use of herbal medicines, increasing body mass index (BMI), systolic blood pressure (SBP), anaemia, reduced cortical thickness and kidney volume. NSAIDs use in excess doses, prolonged period or in stressed state increases the risk for kidney dysfunction, caution is therefore needed to avoid taking these drugs in these conditions.