A higher risk for knee and hip replacement was associated with a set of demographic factors in individuals who are diagnosed with osteoarthritis by a general practitioner, according to a real-world cohort study published in Osteoarthritis Cartilage.
The practice data of patients from Spain who received an incident knee (n=48,311) or hip osteoarthritis (n=15,105) diagnosis were used for the analysis. Associations between the risk for knee/hip replacement with sex, comorbidities, socioeconomic status, body mass index (BMI), and smoking status were examined. The cumulative incidences of knee and hip replacement over a 9-year period (from 2006 to 2015) were assessed. Patients’ BMI was defined according to World Health Organization parameters.
A total of 2561 patients who had a knee osteoarthritis diagnosis underwent knee replacement during the 9-year period (cumulative incidence, 9.4%; 95% CI, 8.9%-9.9%), and 1247 of the patients with hip osteoarthritis underwent hip replacement (cumulative incidence, 11.6%; 95% CI, 10.9%-12.3%).
The average lifetime risks for knee replacement and hip replacement were 30% (95% CI, 25%-36%) and 14% (95% CI, 10%-19%), respectively. Younger women vs men had a higher lifetime risk for knee replacement (eg, at age 60: women, 37%; 95% CI, 27%-50% vs men, 30%; 95% CI, 22%-46%). Men had a higher lifetime risk for hip replacement compared with women (eg, at age 60: men, 30%; 95% CI, 25%-36%; women, 17%; 95% CI, 12%-24%). A higher BMI was also associated with a higher lifetime risk for knee replacement.
Study limitations were the sole inclusion of patients from Spain and the analysis of data from a limited time window.
“The risk of undergoing a knee and hip replacement peaks in the second year after diagnosis, then falls off,” noted the study authors. “There is a sizeable proportion of patients whom referral to surgery is made shortly following diagnosis.”
Burn E, Murray DW, Hawker GA, Pinedo-Villanueva R, Prieto-Alhambra D. Lifetime risk of knee and hip replacement following a GP diagnosis of osteoarthritis: a real-world cohort study [published online June 17, 2019]. Osteoarthritis Cartilage. doi:10.1016/j.joca.2019.06.004