Compared with the general population, 20% of people with osteoarthritis (OA) experience depressive symptoms.1 However, depression is a complex, heterogenous comorbidity of OA and other rheumatic diseases. It manifests and affects each person differently and influences multiple aspects of arthritis care, according to Alan Rathbun, PhD, MPH.
Dr. Rathbun hopes his research, which seeks to characterize the etiology and role of depression in osteoarthritis (OA), will help physicians and rheumatologists think differently about and better understand the effects and interactions of depression in their patients who live with OA. “Understanding is still very limited [about] how these conditions interact with each other in the real-world clinical setting,” he notes. “There [is] also a lack of effective depression prevention and treatment strategies routinely implemented by generalist and specialist practitioners who see OA patients.”
Through funding support from a Rheumatology Research Foundation Scientist Development Award, Dr. Rathbun, a research associate faculty at the University of Maryland School of Medicine in Baltimore and Special Fellow within the VA Maryland Health Care System, is shedding light on these gray areas, using an innovative causal framework and data from the Osteoarthritis Initiative. His research has four primary aims:
- Identify depression subtypes among individuals with knee OA and describe how they change over time;
- Evaluate the dynamic effect of OA disease severity on depressive symptoms;
- Assess the dynamic effect of depressive symptoms on OA disease severity; and
- Determine whether depressive symptoms modify the effect of dynamic analgesic treatments on OA disease severity.2,3
“Rather than assess the presence and effects of depression as the absence or presence of symptomology or a severity continuum, the first aim of the work I have proposed strives to evaluate depressive symptoms based on the identification of distinct subtypes that are characterized by unique and observable constellations of symptoms,” he explains.
His initial study findings among those who have or are at risk for knee OA indicate the presence of four distinct depressive symptom subtypes: 1) no symptoms, 2) moderate symptoms, 3) moderate-melancholic symptoms and 4) severe symptoms. He also has found these subtypes differ in prevalence and clinical presentation by sex. Example: The moderate symptoms subtype was characterized by sadness and anhedonia, and occurred more frequently in men than women. But the severe symptoms subtype occurred more frequently in women than men. Also, comorbidity scores, gait speed, pain scores and analgesic use were significantly associated with subtype among both sexes. Radiographic evidence of knee OA was significant only in men, whereas body mass index was significant only in women. He will be sharing his abstract, “Sex Differences in Depressive Symptom Subtypes in Knee Osteoarthritis,” at the 2017 ACR/ARHP Annual Meeting in a poster session on Monday, Nov. 6 at 9 a.m.