Risk Factors for the Onset of Frozen Shoulder in Middle-Aged and Elderly Subjects Within 1 Year of Discharge From a Hospitalization That Involved Intravenous Infusion: A Prospective Cohort Study

Aim To investigate the incidence of frozen shoulder and risk factors for the onset of frozen shoulder in middle-aged and elderly subjects within 1 year of discharge from a hospitalization that involved intravenous infusion in Zhangjiagang Second People's Hospital. Methods A total of 1,900 subjects who were discharged from a hospitalization that involved intravenous infusion in the hospital between May 2020 and September 2020 met the inclusion criteria for this study: 950 subjects had a mean daily duration of intravenous infusion ≤ 2 h (low exposure) and 950 subjects had a mean daily duration of intravenous infusion ≥3 h (high exposure). Subjects were followed up by telephone at 6 months ± 1 week and 12 months ± 1 week after discharge the incidence of frozen shoulder. Results The cumulative incidence rate of frozen shoulder within 1 year of discharge was 5.2%. Multivariate logistic regression analysis revealed the risk of frozen shoulder was higher in subjects with a mean daily duration of intravenous infusion ≥3 h compared to ≤ 2 h (OR = 3.082, 95% CI 1.919–4.949, P < 0.001); subjects hospitalized for 11–30 days had a higher risk of frozen shoulder compared to those hospitalized for 10 days or less (OR = 6.836, 95%CI 4.363–10.709, P < 0.001); subjects who were overweight/ obese (BMI ≥ 25 kg/m2) had a higher risk of frozen shoulder compared to those of normal weight (BMI 18.5–24.9 kg/m2) (OR = 2.166, 95%CI 1.376–3.410, P = 0.001); subjects in the 56–70-year-old age group had a higher risk of developing frozen shoulder compared to those in the 40–55-year-old age group (OR = 1.977, 95%CI 1.154–3.387, P = 0.013); diabetes increased the risk of frozen shoulder (OR = 3.009, 95%CI 1.826–4.959, P < 0.001). The 71–85 years old age group and hypertension were statistically significant in univariate analysis but not in multivariate analysis (P > 0.05). Conclusion Compared with middle-aged and elderly in the general population, middle-aged and elderly subjects who received intravenous infusion during a hospitalization had a higher cumulative incidence rate of frozen shoulder within 1 year after discharge. Independent risk factors for the onset of frozen shoulder included mean daily duration of intravenous infusion ≥3 h, length of hospital stay 11–30 days, BMI ≥ 25 kg/m2, age 56–70 years, and diabetes.