Patients Lost to Follow-up in Shoulder Arthroplasty: Descriptive Characteristics and Reasons

The purpose of this study was to determine the number of patients lost to follow-up yearly in shoulder arthroplasty and investigate the characteristics of the patients lost to follow-up that may differ from those not lost to follow-up.

All shoulder arthroplasties performed from January 2008 to December 2014 were retrospectively reviewed. The number of patients lost to follow-up was determined yearly. Independent variables included age, sex, body mass index (BMI), diagnosis, type of prostheses, living condition, smoking, alcohol intake, American Society of Anesthesiologists (ASA) score, in-hospital length, surgery length, living area, preoperative Constant score, last Constant score available, and complications. Number of deaths was recorded.

This study included 251 patients. There was an accumulation of 86 patients (34.3%) lost to follow-up after a maximum of 8 years. During the first year, 9.9% of the patients were lost to follow-up, 18.3% in the second year, 25.1% in the third year, 28.7% in the fourth year, 31.5% in the fifth year, 33.9% in the sixth year, and 34.3% in the seventh year. Patients with severe obesity had 2.44 times greater risk of being lost to follow-up (hazard ratio [HR], 2.44; p < 0.001). Elderly patients were also at higher risk (HR, 1.05; p < 0.001). Increases in the ASA score raised the risk of being lost (HR, 1.93; p < 0.001). Patients with complications had a lower risk (43%) of being lost (HR, 0.57; p = 0.018) at the 8-year follow-up. At the 2-year follow-up, the patients with acute fractures and fracture sequelae had a higher risk of being lost to follow-up (HR, 2.44; p = 0.002), and the patients with complications were not significantly different from those without complications (HR, 0.54; p = 0.12).

The longer the follow-up in shoulder arthroplasty, the greater the number of patients lost to follow-up, reaching 34.3% by the seventh year. Patients lost to follow-up were not random in shoulder arthroplasty: older patients, severely obese patients, and those with higher ASA scores were at higher risk of being lost to follow-up, but reasons for being lost to follow-up changed through time and depending on when they were assessed.