Table 1.
Demographic characteristics and trends in prevalence and incidence of patients with knee osteoarthritis in the Intego registry (1996–2015)
| Year 1996* |
Year 2015* |
Overall trend† | Trend 1 | Trend 2 | Trend 3 | ||||
| % | % | AAPC (95% CI) | Years | APC (95% CI) |
Years | APC (95% CI) |
Years | APC (95% CI) |
|
| Prevalence | |||||||||
| Total | 1.99 | 3.56 | 2.5 (2.2 to 2.9) | 1996–2015 | 2.5 (2.2 to 2.9) | ||||
| Men | 1.32 | 2.59 | 3.1 (2.7 to 3.5) | 1996–2015 | 3.1 (2.7 to 3.5) | ||||
| Women | 2.64 | 4.55 | 2.4 (2.0 to 2.7) | 1996–2015 | 2.4 (2.0 to 2.7) | ||||
| Prevalence by age group‡ | |||||||||
| 25–34 | 0.68 | 1.82 | 4.7 (3.7 to 5.6) | 1996–2007 | 7.7 (6.4 to 9.1) | 2007–2015 | 0.6 (−0.9 to 2.1) | ||
| 35–44 | 0.70 | 2.21 | 5.5 (4.3 to 6.7) | 1996–2011 | 4.5 (3.6 to 5.4) | 2011–2015 | 9.5 (4.3 to 15.0) | ||
| 45–54 | 1.55 | 3.14 | 4.0 (3.3 to 4.8) | 1996–2011 | 3.4 (2.8 to 4.0) | 2011–2015 | 6.5 (3.2 to 10.0) | ||
| ≥45 | 3.68 | 7.42 | 2.8 (2.5 to 3.2) | 1996– 2015 | 2.8 (2.5 to 3.2) | ||||
| ≥45 Males | 2.53 | 5.64 | 3.9 (3.6 to 4.3) | 1996– 2015 | 3.9 (3.6 to 4.3) | ||||
| ≥45 Females | 5.26 | 9.03 | 2.4 (2.0 to 2.7) | 1996– 2015 | 2.4 (2.0 to 2.7) | ||||
| 55–64 | 2.96 | 5.60 | 3.0 (2.6 to 3.4) | 1996–2015 | 3.0 (2.6 to 3.4) | ||||
| 65–74 | 6.08 | 8.97 | 1.7 (1.3 to 2.2) | 1996–2015 | 1.7 (1.3 to 2.2) | ||||
| 75–84 | 7.80 | 13.9 | 2.6 (2.0 to 3.2) | 1996–2007 | 3.6 (2.7 to 4.5) | 2007–2015 | 1.2 (0.2 to 2.1) | ||
| ≥85 | 6.27 | 15.0 | 3.0 (2.4 to 3.5) | 1996–2015 | 3.0 (2.4 to 3.5) | ||||
| Incidence | |||||||||
| Total | 0.42 | 0.38 | −0.5 (−1.4 to 0.5) | 1996–2006 | −2.6 (−4.0 to − 1.1) | 2006–2015 | 1.9 (0.4 to 3.5) | ||
| Men | 0.27 | 0.26 | −0.2 (−1.4 to 1.1) | 1996–2006 | −2.5 (−4.4 to − 0.5) | 2006–2015 | 2.5 (0.5 to 4.5) | ||
| Women | 0.58 | 0.49 | −0.5 (−2.4 to 1.4) | 1996–1999 | −8.7 (−16.2 to − 0.6) | 1999–2013 | −0.4 (−1.2 to 0.5) | 2013–2015 | 11.8 (−3.3 to 29.3) |
| ≥45 | 0.79 | 0.69 | 0.0 (−1.4 to 1.4) | 1996–2011 | −1.3 (−2.2 to −0.3) | 2011–2015 | 4.7 (−1.5 to 11.4) | ||
| ≥45 Males | 0.44 | 0.51 | 0.6 (−0.4 to 1.6) | 1996–2015 | 0.6 (−0.4 to 1.6) | ||||
| ≥45 Females | 1.11 | 0.81 | −1.9 (−3.7 to 0) | 1996–1999 | −11 (−21.4 to 0.7) | 1999–2015 | 0.0 (−0.9 to −0.8) | ||
Statistically significant differences for (average) annual percentage change (APC) are indicated in bold.
*These percentages are standardised for the total Flemish population.
†Joinpoint regression modelling was used to estimate (average) APC in prevalence and incidence trends. Three possible trends were calculated during the 20-year study period.
‡Standardisation was possible for the total population, but not for specific age cohorts.
AAPC, average annual percentage change.