Combination of Comorbid Obesity and Depression Increases Risk of Progression of Knee Osteoarthritis
Takeaways
- This analysis of a U.S. claims database aimed to identify subsets of patients with knee osteoarthritis (OA) who may be at greater risk of more rapid progression.
- Information was compared on four cohorts of 274,403 unique individuals (1,097,612 total): those with depression only, obesity only, depression+obesity, or neither diagnosis.
- The incidence of total knee arthroplasty (TKA) within five years after OA diagnosis was significantly greater for those with comorbid depression and obesity than those without either comorbidity (RR=1.43; P<0.0001).
- Similarly, the incidence of TKA was significantly greater for those with comorbid depression and obesity than those with each comorbidity individually (vs. obesity cohort, RR=1.13; P<0.0001; vs. depression cohort, RR=1.53; P<0.0001).
- It remains to be seen in clinical trials whether interventions targeting lifestyle differences such as diet and exercise can benefit this subgroup at greatest risk of undergoing TKA.
Some 15% to 30% of patients with knee osteoarthritis (OA) experience rapid progression of cartilage degradation, knee pain, and disability rather than slow progression over many years. Obesity and depression are each individually associated with worse OA pain and pain progression.
Now, Joanne Borg-Stein, MD, director of the Wellesley Outpatient Center of Spaulding Rehabilitation, and colleagues have identified the combination of obesity and depression as a risk factor for more rapid OA progression. Their findings appear in The Journal of Rheumatology.
Methods
A query of claims stored in the PearlDiver Mariner Ortho157 database between January 2010 and October 2021 identified 3,935,585 individuals with knee OA who were sorted into four cohorts:
- Depression only
- Obesity only
- Depression + Obesity
- Control — No diagnosis associated with depression or obesity
The cohorts were then matched 1:1:1:1 by age, sex and Charlson Comorbidity Index. That process resulted in four cohorts of 274,403 unique individuals (1,097,612 total). 180,563 individuals in each cohort were women and the mean age in each cohort was 55.
Results
Within five years after OA diagnosis, the incidence of total knee arthroplasty (TKA) was:
- Greater for the Obesity group than the Control group — RR=1.23 (P<0.0001)
- Greatest for the Depression+Obesity group — RR=1.43 compared with the Control group (P<0.0001)
- Greater for the Depression+Obesity group than either the Obesity group (RR=1.13; P<0.0001) or the Depression group (RR=1.53; P<0.0001)
- Lower in the Depression group than the Control group — RR=0.94 (95% CI, 0.92–0.95); although statistically significant, the magnitude of the reduction in the incidence of TKA (6%) may not be clinically relevant
Implications for Rehabilitation Clinics
The combination of knee OA, obesity and depression can make it difficult for people to initiate and maintain routine exercise regimens, creating a cycle of pain, inactivity and cartilage degradation. Breaking that cycle may result in less pain and more optimal loading of the articular cartilage, thereby preventing further cartilage loss. What's more, depression and obesity are independent risk factors for poor outcomes after TKA.
Still, it remains to be seen in clinical trials whether lifestyle differences such as diet and exercise contribute to the increased incidence of TKA for those with comorbid depression and obesity. It's hoped targeted interventions can be developed to benefit this subgroup at greatest risk of undergoing TKA.
Key Stats
- 43% greater five-year risk of total knee arthroplasty among individuals with knee osteoarthritis who had comorbid obesity and depression than those who had neither comorbidity
- 13% greater five-year risk of total knee arthroplasty among individuals with knee osteoarthritis who had comorbid obesity and depression than those who had only comorbid obesity
- 53% greater five-year risk of total knee arthroplasty among individuals with knee osteoarthritis who had comorbid obesity and depression than those who had only comorbid depression