Comparison of Fractures Among Older Adults Who Are Ambulatory vs Those Who Use Wheelchairs in Sweden

Abstract

ImportanceSeveral diseases and conditions, such as cerebrovascular disease, arthritis, previous fractures, neurological diseases, or amputation, can result in severe immobility justifying wheelchair use for increased mobility. Immobility results in disuse osteoporosis and is considered a risk factor for fracture, although there are no large cohort studies that have investigated fracture risk in patients who use wheelchairs compared with an ambulatory control group.ObjectiveTo investigate whether immobilized adults who used wheelchairs had a different risk of fracture and injurious falls compared with matched ambulatory controls.Design, Setting, and ParticipantsThis retrospective cohort study compared patients who used wheelchairs and controls (propensity score matched 1:1 using 22 variables relating to anthropometrics, general condition, comorbidity, and fall and fracture risk), identified through a national database of adults 65 years or older who underwent a health evaluation (baseline) at Swedish health care facilities. Patients were followed up from January 1, 2007, to December 31, 2017, and data analysis was performed between June 1 and 30, 2022.Main Outcomes and MeasuresIncident fracture, injurious falls without fracture, and deaths.ResultsA total of 55 442 adults using wheelchairs were included in the analysis (mean [SD] age, 83.2 [8.3] years; 60.5% women). Those who used wheelchairs and the 55 442 matched controls were followed up for a median of 2.0 (IQR, 0.5-3.2) and 2.3 (IQR, 0.8-3.6) years, respectively. Patients who used wheelchairs had a lower risk of any fracture (hazard ratio [HR], 0.43 [95% CI, 0.41-0.44]), major osteoporotic fracture (HR, 0.32 [95% CI, 0.31-0.33]), and hip fracture (HR, 0.30 [95% CI, 0.28-0.32]) compared with the ambulatory controls, associations that were only marginally affected by multivariable (same as the matching variables) adjustment. The risk of fall injury was lower among those who used wheelchairs than among ambulatory controls (unadjusted HR for Cox proportional hazards models, 0.48 [95% CI, 0.47-0.50]) and remained highly similar after adjustments. Patients who used wheelchairs had a significantly increased risk of death (HR, 1.35 [95% CI, 1.33-1.36]) compared with controls. Association between wheelchair use and fracture outcomes and injurious falls, calculated using a Fine and Gray model with death as a competing risk, was similar to associations obtained using Cox proportional hazards regression for all fracture outcomes.Conclusions and RelevanceIn this retrospective cohort study of older adults, wheelchair use was associated with a lower risk of fracture than observed in ambulatory controls. These findings suggest that immobility associated with wheelchair use should not be considered a risk factor for fracture.