Pain was the main driver of seeking medical care in an Arthritis Care & Research study of patients with osteoarthritis. In addition to pain, insomnia and depression increased health care use.

In the study of 2976 patients, half of participants presented with at least one of the three symptoms (pain, insomnia, depression), and approximately 34% and 29% suffered from insomnia or depression, respectively, in addition to moderate to severe pain.

The combined effects of pain and insomnia, and pain and depression were additive and increased diverse types of health care use, and these effects increased greatly with increasing insomnia and depression severity after controlling for pain.

The findings indicate the important role that concurrent symptomatic conditions may play in increasing use of health care services.

"Pain, insomnia, and depression are common in older adults with osteoarthritis. Unfortunately, they commonly occur together," said lead author Dr. Minhui Liu, of Johns Hopkins University School of Nursing. "To our knowledge, our study is the first to examine their effects on diverse health care use. We are glad to find that although their effects on health care use are substantial, their combined effects are not greater than the sum of their individual effects, which is good for patients."