Objective: To examine the relationship between long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) and the incidence and progression of radiographic hip osteoarthritis (RHOA), as well as the degeneration of individual radiographic features.

Methods: We analyzed data from the Osteoarthritis Initiative (OAI) and the Cohort Hip and Cohort Knee (CHECK) study. Our exposure was the number of years of NSAID use over a 4-to-5-year follow-up period. Our outcomes were the incidence and progression of RHOA over a 4-to-5-year follow-up as assessed using a modified Croft grade in OAI and the Kellgren-Lawrence (K/L) grade in CHECK. The incidence of RHOA was defined as having RHOA (grade ≥2) at follow-up and investigated in "incidence cohorts" of hips without RHOA at baseline (grade <2). The progression of RHOA was defined as an increase of ≥1 grade at follow-up from baseline and investigated in "progression cohorts" of hips with RHOA at baseline (grade ≥2). Additionally, we assessed the degeneration of nine specific radiographic features, such as joint space narrowing and osteophytes, defined by a grade increase of ≥1 ​at follow-up from baseline, in all cohorts.

Results: In the incidence cohorts, there were 5153 hips in OAI and 1011 in CHECK; in the progression cohorts, there were 285 and 106 hips, respectively. There was no association between NSAID use and the outcomes investigated.

Conclusion: Over 4-to-5 years, long-term NSAID use showed no association with the incidence or progression of RHOA, or with the degeneration of individual radiographic features.