Disparities in the age at osteoarthritis diagnosis: an indicator for equity-focused prevention.

Abstract

Dear Editor, Primary prevention of OA aims to extend OA-free life expectancy for joints. Calls for more coherent and concerted preventive action highlight a number of challenges: they include appropriate methods and metrics to monitor and evaluate action [1, 2]. We propose a visual population health metric, obtainable from routinely available data, that may be useful for equity-focused monitoring of OA prevention in populations. It draws on classic work by van Saase and colleagues [3] who noted a strong tendency towards ‘parallelism’ (populations differ in their level of OA but not in their age-related slopes), by Brenner et al. [4] on prevention as rate postponement and a recent comprehensive analysis of the age at disease onset using national primary care electronic healthcare record (EHR) data [5]. We used data from the Clinical Practice Research Datalink Aurum database linked to the Index of Multiple Deprivation (IMD) 2015, an area-based measure of deprivation based on patient residential postcode. Using previously established methods of a standard code list of OA diagnostic codes, a 3-year look-back period to exclude prevalent consulters and exact person-time for denominator, we identified cases of incident (first) recorded diagnosis of OA in 2019 in England, in adults aged 45 years and over, stratified by IMD deciles (national ranking) [6]. We used kernal density plots to display the age distribution of incident OA cases in the least and the most deprived deciles weighted to the mid-2019 English population.