Smoking, Obesity Increase Risk for Trajectories of Depression and Comorbidities in Patients With Knee Osteoarthritis

Older patient with osteoarthritis of the knee
Older patient with osteoarthritis of the knee
Researchers identified trajectories of depression and comorbidity in patients with knee osteoarthritis, and described the characteristics of distinctive trajectories.

Depression and comorbidities in patients with knee osteoarthritis (OA) is significant and worsened by risk factors, including obesity and smoking, according to study results published in Clinical Rheumatology.

The association between knee OA and depression is bidirectional. Somatic comorbidities also have a similar relationship with knee OA.

This study examined the trajectories of depression and comorbidities in patients with knee OA and the risk factors associated with worsening trajectories.

Patients with or at risk for knee OA in the Osteoarthritis Initiative (OAI) were included in the current study if they had no significant comorbidities or depression symptoms at baseline. Patients were followed up with for 10 years and evaluated every year for depression symptoms and every 2 years for comorbidities, including cancer, diabetes, dementia, congestive heart failure, and other chronic diseases. Group-based trajectory modeling was performed to describe patient outcomes over time. Baseline characteristics were used to investigate risk factors of the worsening trajectory group.

Among 2833 patients with OA, 2 comorbidity trajectories were identified: a stable trajectory (70.4%) and a worsening trajectory (29.6%). Risk factors for a worsening trajectory of comorbidity were obesity (odds ratio [OR], 1.47; 95% CI, 1.20-1.79; P <.001), older age (OR, 1.74; 95% CI, 1.41-2.16; P <.001), and smoking (OR, 1.30; 95% CI, 1.08-1.57; P <.01) at baseline. For depression, the researchers identified stable (52%), slow-worsening (40.5%), and fast-worsening (7.5%) trajectories. Risk factors for the fast-worsening trajectory of depression were female sex (OR, 1.51; 95% CI, 1.03-2.20; P <.05), lower income (OR, 1.52; 95% CI, 1.01-2.27; P <.05), and smoking (OR, 1.30; 95% CI, 1.08-1.57; P <.01) at baseline.

Limitations of the study included the exclusion of patients with depression symptoms at baseline, inclusion of patients with knee OA at baseline before the onset of depression and comorbidities, inability to determine causative pathways and relationships, infrequent measurement of depression and comorbidity, and absence of some risk factors in the OAI database.

“Thirty percent of [patients] with [knee] OA followed a continuously worsening trajectory of comorbidity, predicted by obesity, older age, and smoking, and 7% subjects with [knee] OA [had] rapid-worsening depression symptoms, predicted by female [sex], lower income, and smoking,” the researchers concluded. “Managing related risk factors, like weight loss or smoking cessation, might have considerable significance in preventing or delaying depression symptoms and comorbidity in [knee] OA.”


Li M, Nie Y, Zeng Y, Wu Y, Liu Y, Wu L, Shen B. The trajectories of depression symptoms and comorbidity in knee osteoarthritis subjects. Clin Rheumatol. Published online September 6, 2021. doi:10.1007/s10067-021-05847-9