Prevalence of multimorbid degenerative lumbar spinal stenosis with knee and/or hip osteoarthritis: protocol for a systematic review and meta-analysis

Background: Lumbar spinal stenosis (LSS) and knee and hip osteoarthritis (OA) are prevalent conditions in the aging population and previous literature suggests they share many symptoms and are present at the same time in patients. However, no prevalence estimates of multimorbid LSS and knee and/or hip OA are currently available. The primary objective of this systematic review is therefore to estimate the prevalence of multimorbid LSS with knee and/or hip OA using radiological, clinical, and combined case definitions. Methods: This systematic review protocol has been designed according to the guidelines from the Cochrane Collaboration and are reported according the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols. A comprehensive search will be performed in the following databases: MEDLINE, EMBASE, CENTRAL, and CINAHL. Web of Science will be used for forward citation tracking. No restriction in the search for publication data and language will be applied, but only articles in English will be included. The search strategy will include the following domains: LSS, knee OA, and hip OA. Retrieved citations will be screened by two authors independently. Disagreements will be discussed until consensus, or a third reviewer will be consulted if consensus cannot be reached. Data extraction and assessment of methodological quality will be done by two authors independently, using a standardized data extraction form and modified Risk of Bias Tool for Prevalence studies. Meta-analysis estimating prevalence with 95% CI will be performed using a random effects model. Meta-regression analyses will be performed to investigate the impact of LSS clinical presentations, sample population, healthcare setting, risk of bias, and other patient characteristics on prevalence estimates for multimorbid LSS and knee and/or hip OA. Discussion: The results of this review will provide the first estimates of the prevalence of multimorbid LSS and hip and knee OA based on various case definitions. The impact of covariates such as LSS clinical presentations, sample population, healthcare setting, risk of bias, and patient characteristics on prevalence estimates will also be presented. These findings will help to better understand the relationship between LSS and knee and/or hip OA and identify future research priorities. Systematic review registration: Submitted to PROSPERO, awaiting registration Keywords: Lumbar spinal stenosis, Hip osteoarthritis, Knee osteoarthritis, Multimorbidity, Prevalence, Systematic review protocol