Researchers at Hospital for Special Surgery (HSS) set out to test this hypothesis. They found that people who lacked good social ties were much more likely to experience serious, ongoing pain following total hip replacement surgery two or more years after the procedure.
The study, titled "Social Networks and Hip Replacement Outcomes in Rheumatoid Arthritis and Osteoarthritis," will be presented at the American College of Rheumatology/Association of Rheumatology Health Professionals Annual Meeting on October 29 in San Diego.
"Previous studies have shown that social isolation is a risk factor for poor health outcomes," said Lisa Mandl, M.D., M.P.H., a rheumatologist at HSS who worked on this study with Danielle Ramsden-Stein, M.D., and colleagues at the hospital.
"Studies show that people who don't have good social ties are at increased risk of suffering a heart attack or stroke, and even dying, compared to those who enjoy the social support of family, friends and the community."
HSS investigators found a strong association between how much pain OA patients continued to have after total hip replacement (THR) and the degree of social isolation they experienced. "About eight percent of the hip replacement patients were very socially isolated," Dr. Mandl said. "There was a strong link between a lack of social interaction and increased pain."
Socially isolated individuals were those with few close contacts-for example, not married, fewer than six friends or relatives, and no membership in either community groups or religious organizations.
For their study, investigators identified cases from a registry of more than 12,000 patients who had primary or revision hip replacement surgery from May 2007 to February 2011 for either osteoarthritis (OA) or rheumatoid arthritis (RA). Cases were validated via chart review to control for both expected differences between patient populations and time since surgery.
Researchers collected demographic information and evaluated patient pain and function using the Western Ontario and Universities Arthritis Index (WOMAC), both pre-operatively and between two and five years after surgery. The WOMAC is a widely-used questionnaire that assesses pain, stiffness and physical function.
In addition, the Berkman-Syme Social Network Index (BSSNI), which measures social integration, was administered between two and five years post-operatively. The BSSNI was divided into four categories, with the "most isolated" category being the referent group.
The survey was sent to 934 patients with a mean age of 62. A total of 146/223 patients with RA (65.5 percent) and 541/711 patients with OA (76.1 percent) responded. Demographics were similar in both groups. Both RA and OA patient groups had similar proportions of very socially isolated patients (8.2 percent and 7.8 percent respectively).
Investigators found that being socially isolated was associated with an almost three times increased risk of having "poor," or severe, pain after THR, controlling for multiple potential confounding factors. "Poor" pain is defined as pain that is as severe as some patients had when they chose hip replacement surgery. In the study, social integration seemed more important for patients who had hip replacement for osteoarthritis, who comprise the vast majority of THR cases.
"We believe further prospective studies should be done to determine whether interventions to evaluate and improve patients' social ties before surgery could lead to a better pain outcome after hip replacement," Dr. Mandl noted. "It could be a way to improve outcomes without medication or other costly interventions. I see no downside to helping patients get the social support they may need to improve their quality of life."