AMSTERDAM – There are four distinct patterns of pain in patients with early presumed hip osteoarthritis, and several factors could help identify patients most likely to experience more severe pain, according to analysis from a Dutch study.
The majority of the 545 patients included in the analysis from the Cohort Hip and Knee (CHECK) study experienced a low or a mild constant hip pain over a 5-year follow-up period (231 patients, 42.4%). Around one-quarter had moderate hip pain with moderate pain progression (132 patients, 24.2%), about one in six (88 patients, 16.1%) had moderate hip pain with moderate pain regression, and the remainder (94 patients, 17.2%) had constant, severe hip pain.
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Factors associated with these pain trajectories included the level of education achieved, ability to cope with pain, the Western Ontario and McMaster Universities Arthritis Index (WOMAC) physical function subscale, and pain experienced from internal rotation of the hip.
The findings were reported at the World Congress on Osteoarthritis sponsored by the Osteoarthritis Research Society International. They were also published online in Osteoarthritis and Cartilage (2106 Feb 5. doi: 10.1016/j.joca.2015.11.023).
Although prior studies examined progression predictors in hip OA, none looked specifically at how pain changes over time, noted study author Dr. Alex Bastick of Erasmus University Medical Center, Rotterdam, the Netherlands. Thus, the current aim was to define the trajectory of hip pain among individuals with early symptoms of hip OA, and identify any baseline factors that might help clinicians predict which pain trajectory patients may follow.
The CHECK study is a 10-year nationwide cohort study of 1,002 participants in the Netherlands with assumed early symptomatic OA of the knee, hip, or both. For the current analysis, Dr. Bastick and his associates considered only those patients with hip pain or stiffness who had completed 5 years of follow-up. At baseline, the mean age of the total population was 55.7 years, and 81% of participants were female. About one-quarter (26%) of participants had a clinical OA diagnosis according to American College of Rheumatology criteria.
Baseline radiographic severity was not associated with the various pain trajectories identified, Dr. Bastick observed, but patients who had achieved a lower level of education were roughly three times more likely to experience severe pain than mild or low constant pain. Patients experiencing severe pain were more likely to use pain transformation as a coping strategy, have higher activity limitation scores, and experience painful internal hip rotation.
Because around 60% of patients follow the mild or moderately progressing pain trajectories, conservative treatment in the early stages of hip OA appears appropriate, Dr. Bastick and his associates suggested. Their findings highlight the importance of a physical examination, and that reassessment of clinical symptoms should perhaps be undertaken in the first year of follow-up.
“Future research should be aimed at measuring symptomatic progression of hip OA with even more frequent symptom assessment,” the researchers proposed.
Reumafonds, the Dutch Arthritis Foundation, funded the study. Dr. Bastick did not have financial disclosures.