Reasons for Readmission Following Primary Total Shoulder Arthroplasty
TAKE-HOME POINTS
- Shoulder arthroplasty is an increasingly commonly performed procedure for shoulder arthritis and other conditions.
- Unplanned readmission in the 30 days after shoulder arthroplasty occurred in about 1 of 40 cases.
- Increasing age was associated with readmission, particularly age >80 years.
- Other risk factors for readmission were male sex, anemia, and dependent functional status.
- The most common reasons for readmission were pneumonia, dislocation, pulmonary embolism, and surgical site infection.
STATISTICAL ANALYSIS
Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.
RESTULTS
A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.
Table 1. Patient Population
,Number | Percent | |
Total | 3627 | 100.0% |
Age | ||
18-59 | 539 | 14.9% |
60-69 | 1235 | 34.1% |
70-79 | 1317 | 36.3% |
≥80 | 536 | 14.8% |
Sex | ||
Male | 1603 | 44.2% |
Female | 2024 | 55.8% |
Body mass index | ||
Normal (<25 kg/m2) | 650 | 17.9% |
Overweight (25-30 kg/m2) | 1147 | 31.6% |
Obese (≥30 kg/m2) | 1830 | 50.5% |
Functional status | ||
Independent | 3544 | 97.7% |
Dependent | 83 | 2.3% |
Diabetes mellitus | ||
No | 3022 | 83.3% |
Yes | 605 | 16.7% |
Dyspnea on exertion | ||
No | 3393 | 93.6% |
Yes | 234 | 6.5% |
Hypertension | ||
No | 1192 | 32.9% |
Yes | 2435 | 67.1% |
COPD | ||
No | 3384 | 93.3% |
Yes | 243 | 6.7% |
Current smoker | ||
No | 3249 | 89.6% |
Yes | 378 | 10.4% |
Anemia | ||
No | 3051 | 84.1% |
Yes | 576 | 15.9% |
Abbreviation: COPD, chronic obstructive pulmonary disease.
In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).
Table 2. Bivariate Analysis of Risk Factors for Readmission
Rate | RR | 95% CI | P-value | |
Age | 0.011 | |||
18-59 | 1.30% | Ref. | - | |
60-69 | 2.02% | 1.6 | 0.7-3.6 | |
70-79 | 2.89% | 2.2 | 1.0-4.9 | |
≥80 | 4.29% | 3.3 | 1.4-7.6 | |
Sex | 0.099 | |||
Female | 2.17% | Ref. | - | |
Male | 3.06% | 1.4 | 0.9-2.1 | |
Body mass index | 0.764 | |||
Normal (<25 kg/m2) | 2.92% | Ref. | - | |
Overweight (25-30 kg/m2) | 2.35% | 0.8 | 0.5-1.4 | |
Obese (≥30 kg/m2) | 2.57% | 0.9 | 0.5-1.5 | |
Functional status | 0.008 | |||
Independent | 2.45% | Ref. | - | |
Dependent | 7.23% | 2.9 | 1.3-6.5 | |
Diabetes mellitus | 0.483 | |||
No | 2.48% | Ref. | - | |
Yes | 2.98% | 1.2 | 0.7-2.0 | |
Dyspnea on exertion | 0.393 | |||
No | 2.51% | Ref. | - | |
Yes | 3.42% | 1.4 | 0.7-2.8 | |
Hypertension | 0.145 | |||
No | 2.01% | Ref. | - | |
Yes | 2.83% | 1.4 | 0.9-2.2 | |
COPD | 0.457 | |||
No | 2.51% | Ref. | - | |
Yes | 3.29% | 1.3 | 0.6-2.7 | |
Current smoker | 0.116 | |||
No | 2.71% | Ref. | - | |
Yes | 1.32% | 0.5 | 0.2-1.2 | |
Anemia | <0.001 | |||
No | 2.16% | Ref. | - | |
Yes | 4.69% | 2.2 | 1.4-3.4 |
Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.
In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).
Table 3. Independent Risk Factors for Readmission on Multivariate Analysis
Rate | RR | 95% CI | P-value | |
Age | 0.027 | |||
18-59 | 1.30% | Ref | - | |
60-69 | 2.02% | 1.6 | 0.7-3.6 | |
70-79 | 2.89% | 2.3 | 1.0-5.1 | |
≥80 | 4.29% | 3.1 | 1.3-7.4 | |
Sex | 0.025 | |||
Female | 2.17% | Ref. | - | |
Male | 3.06% | 1.6 | 1.1-2.4 | |
Anemia | 0.005 | |||
No | 2.16% | Ref | - | |
Yes | 4.69% | 1.9 | 1.2-3.0 | |
Functional status | 0.012 | |||
Independent | 2.45% | Ref | - | |
Dependent | 7.23% | 2.8 | 1.3-6.2 |
Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.
Continue to: Table 4...
