Table 2.
Incidence rate ratios (IRR) and their 95% credible intervals (CI 95%) obtained from Markov chain Monte Carlo Poisson regression models for regional variation of hip (THA) and knee (TKA) arthroplasty in two time-periods
| THA 2010–2013 | THA 2014–2017 | TKA 2010–2013 | TKA 2014–2017 | |
|---|---|---|---|---|
| Variable | IRR (CI 95%) | IRR (CI 95%) | IRR (CI 95%) | IRR (CI 95%) |
| Gender | ||||
| Male | 1.00 | 1.00 | 1.00 | 1.00 |
| Female | 1.10 (1.08–1.13) | 1.15 (1.13–1.18) | 1.67 (1.63–1.71) | 1.64 (1.61–1.68) |
| Age (years old) | ||||
| –49 | 1.00 | 1.00 | 1.00 | 1.00 |
| 50–54 | 4.76 (4.44–5.08) | 5.68 (5.30–6.06) | 7.15 (6.70–7.65) | 7.40 (6.96–7.88) |
| 55–59 | 8.53 (7.96–9.12) | 9.40 (8.71–10.03) | 13.74 (12.85–14.69) | 14.16 (13.34–15.05) |
| 60–64 | 12.35 (11.52–13.16) | 12.66 (11.85–13.50) | 18.68 (17.51–19.88) | 17.80 (16.81–18.98) |
| 65–69 | 17.70 (16.67–18.83) | 18.25 (17.09–19.41) | 23.67 (22.25–25.25) | 22.94 (21.74–24.48) |
| 70–74 | 23.80 (22.44–25.42) | 22.79 (21.38–24.10) | 33.74 (31.74–35.85) | 28.44 (26.82–30.25) |
| 75–79 | 25.72 (24.16–27.48) | 25.65 (24.01–27.15) | 35.41 (33.12–37.69) | 31.05 (29.25–33.07) |
| 80 + | 14.65 (13.51–15.67) | 15.93 (14.86–17.05) | 18.49 (17.23–19.63) | 16.76 (15.71–17.98) |
| No. comorbidities | ||||
| 0 | 1.00 | 1.00 | 1.00 | 1.00 |
| 1 | 1.09 (1.05–1.14) | 1.13 (1.10–1.17) | 1.30 (1.26–1.34) | 1.37 (1.32–1.40) |
| 2 + | 0.83 (0.78–0.88) | 0.89 (0.83–0.95) | 1.01 (0.95–1.06) | 1.09 (1.03–1.14) |
| Education | ||||
| Lower | 1.00 | 1.00 | 1.00 | 1.00 |
| Secondary | 0.99 (0.96–1.02) | 0.99 (0.96–1.02) | 0.97 (0.95–1.00) | 1.03 (1.01–1.06) |
| Higher | 0.93 (0.89–0.97) | 0.94 (0.91–0.97) | 0.70 (0.68–0.73) | 0.80 (0.77–0.82) |
| Occupation | ||||
| Higher non-manual | 1.00 | 1.00 | 1.00 | 1.00 |
| Lower non-manual | 0.99 (0.94–1.03) | 1.03 (1.00–1.07) | 1.07 (1.02–1.11) | 1.11 (1.07–1.15) |
| Manual | 1.00 (0.95–1.05) | 0.99 (0.95–1.04) | 1.13 (1.09–1.19) | 1.15 (1.11–1.20) |
| Farmer | 1.41 (1.34–1.51) | 1.41 (1.35–1.49) | 1.44 (1.37–1.53) | 1.46 (1.38–1.54) |
| Other | 0.99 (0.95–1.05) | 1.00 (0.96–1.06) | 1.03 (0.98–1.09) | 1.05 (1.01–1.11) |
| Income quintile | ||||
| Highest | 1.00 | 1.00 | 1.00 | 1.00 |
| 4 | 0.98 (0.94–1.02) | 0.96 (0.92–1.00) | 1.05 (1.01–1.09) | 0.97 (0.93–1.00) |
| 3 | 1.00 (0.96–1.04) | 0.95 (0.92–0.99) | 1.02 (0.98–1.06) | 0.96 (0.93–1.00) |
| 2 | 0.98 (0.94–1.02) | 0.93 (0.90–0.97) | 0.98 (0.94–1.01) | 0.89 (0.86–0.92) |
| Lowest | 0.81 (0.77–0.85) | 0.72 (0.69–0.76) | 0.74 (0.72–0.78) | 0.64 (0.62–0.67) |
| Musculoskeletal disorder index (+ 1SD) | 1.05 (1.02–1.09) | 1.03 (0.98–1.08) | 1.08 (1.01–1.15) | 1.07 (1.01–1.13) |