Systematic review and meta-analysis of observational studies to check the protective role of non-steroidal anti-inflammatory drugs in Alzheimer's disease

Alzheimer's disease (AD) is a major neurodegenerative disease, affecting more than two third cases of dementia in the world. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used anti-inflammatory analgesic agents representing 7.7% of worldwide prescriptions of which 90% are in patients over 65 years old. Based on mixed findings a systematic review and meta-analysis were conducted to develop a better understanding of the protective role of NSAIDs in AD. We used three database PubMed, Web of Science, and Embase to identify the literatures. The studies following cohort and case-control design were investigated separately to check the effect of NSAIDs on AD, by the using their fundamental indicators (relative risk and odds ratio). The fixed effect or random effects model were used to estimate the pooled relative risk and pooled odds ratio separately for both the study design, based on magnitude of heterogeneity. A total of 14 studies were selected for meta-analysis. Eight studies were following cohort study design, whereas, six studies were following case-control study design. In meta-analysis of cohort studies, the pooled relative risk was 0.67 with 95% C.I 0.39 to 1.15, which was statistically insignificant. In meta-analysis of case-control studies, the pooled odds ratio was 0.71 with 95% C.I 0.46 to 1.10, which was statistically insignificant. NSAIDs do not act as a protective factor for Alzheimer's disease. Additionally, methodologically sound randomized controlled trials are required to produce a robust result.