Table 2 Patient Characteristics Before Matching
From: Reducing selection bias in case-control studies from rare disease registries
| Â | Patients with Avascular Necrosis | Patients without Avascular Necrosis | Odds Ratio | 95% Confidence Interval |
|---|---|---|---|---|
Before Matching | 853 | 4127 | Â | Â |
Gender, n (%) | Â | Â | Â | Â |
Male | 423 (49·6) | 1899 (46·0) | Reference* |  |
Female | 430 (50·4) | 2228 (54·0) | 0·89 | (0·78, 1·02) |
Year of Birth, n (%) | Â | Â | Â | Â |
1910 - < 1920 | 4 (0·5) | 34 (0·8) | 0·49 | (0·18, 1·31) |
1920 - < 1930 | 21 (2·5) | 125 (3·0) | 0·66 | (0·42, 1·05) |
1930 - < 1940 | 75 (8·8) | 198 (4·8) | 1·27 | (0·96, 1·68) |
1940 - < 1950 | 114 (13·4) | 384 (9·3) | 1·06 | (0·83, 1·35) |
1950 - < 1960 | 146 (17·1) | 529 (12·8) | Reference* |  |
1960 - < 1970 | 147 (17·2) | 590 (14·3) | 0·92 | (0·73, 1·16) |
1970 - < 1980 | 156 (18·3) | 665 (16·1) | 0·88 | (0·70, 1·10) |
1980 - < 1990 | 129 (15·1) | 659 (16·0) | 0·76 | (0·60, 0·96) |
1990 - < 2000 | 58 (6·8) | 633 (15·3) | 0·39 | (0·29, 0·53) |
2000 - < 2010 | 3 (0·4) | 310 (7·5) | 0·04 | (0·01, 0·14) |
Treatment Status, n (%) | Â | Â | Â | Â |
Untreated | 35 (4·1) | 995 (24·1) | Reference* |  |
Treated | 818 (95·9) | 3132 (75·9) | 6·09 | (4·34, 8·55) |
Splenectomy Status, n (%) | Â | Â | Â | Â |
Spleen Intact | 438 (51·3) | 3407 (82·6) | Reference* |  |
Splenectomized | 415 (48·7) | 720 (17·4) | 3·21 | (2·81, 3·67) |