Table 1.
Baseline Characteristics of Categorical Variables by Arthritis Status
| No Arthritis* (n=83,295) |
OA* (n=63,402) |
RA* (n=960) |
||||
|---|---|---|---|---|---|---|
| N | % | N | % | N | % | |
| Baseline Age Group | ||||||
| 50–59 | 33,804 | 40.58 | 15,378 | 24.25 | 240 | 25.00 |
| 60–69 | 35,446 | 42.55 | 30,248 | 47.71 | 448 | 46.67 |
| 70–79 | 14,045 | 16.86 | 17,776 | 28.04 | 272 | 28.33 |
| Race/Ethnicity | ||||||
| White | 68,699 | 82.68 | 53,153 | 84.05 | 741 | 77.35 |
| Hispanic | 3,573 | 4.30 | 2,060 | 3.26 | 38 | 3.97 |
| African American | 6,817 | 8.20 | 5,857 | 9.26 | 126 | 13.15 |
| Asian | 2,721 | 3.28 | 1,191 | 1.88 | 26 | 2.71 |
| American Indian | 317 | 0.38 | 292 | 0.46 | 9 | 0.94 |
| Unknown | 967 | 1.16 | 686 | 1.09 | 18 | 1.88 |
| Hormone Trial | ||||||
| Not randomized | 68,819 | 82.62 | 53,487 | 84.36 | 878 | 91.46 |
| Intervention | 7,374 | 8.85 | 4,887 | 7.71 | 41 | 4.27 |
| Control | 7,102 | 8.53 | 5,028 | 7.93 | 41 | 4.27 |
| Dietary Modification Trial | ||||||
| Not randomized | 57,310 | 68.80 | 45,779 | 72.20 | 812 | 84.58 |
| Intervention | 10,398 | 12.48 | 7,069 | 11.15 | 59 | 6.15 |
| Control | 15,587 | 18.71 | 10,554 | 16.65 | 89 | 9.27 |
| Calcium and Vitamin D Trial | ||||||
| Not randomized | 63,522 | 76.26 | 50,503 | 79.66 | 866 | 90.21 |
| Intervention | 9,906 | 11.89 | 6,434 | 10.15 | 53 | 5.52 |
| Control | 9,867 | 11.85 | 6,465 | 10.20 | 41 | 4.27 |
| Hospitalized in Last 2 Years | ||||||
| No | 69,909 | 88.43 | 51,453 | 81.59 | 683 | 72.05 |
| Yes | 9,143 | 11.57 | 11,607 | 18.41 | 265 | 27.95 |
| Number of Falls in 12 Months | ||||||
| 0 | 57,007 | 71.34 | 40,530 | 64.10 | 612 | 64.15 |
| 1 | 15,054 | 18.84 | 13,331 | 21.08 | 201 | 21.07 |
| 2 | 5,454 | 6.83 | 6,123 | 9.68 | 97 | 10.17 |
| 3+ | 2,398 | 3.00 | 3,248 | 5.14 | 44 | 4.61 |
| Parental Fracture >40 Years | ||||||
| No | 47,303 | 61.00 | 34,447 | 59.34 | 547 | 62.37 |
| Yes | 30,242 | 39.00 | 23,605 | 40.66 | 330 | 37.63 |
| Fracture at Age 55+ | ||||||
| No | 52,476 | 85.93 | 43,140 | 81.24 | 631 | 80.08 |
| Yes | 8,595 | 14.07 | 9,961 | 18.76 | 157 | 19.92 |
| Smoking Status | ||||||
| Never smoked | 42,597 | 51.69 | 31,502 | 50.34 | 437 | 46.00 |
| Past smoker | 33,770 | 40.98 | 27,124 | 43.35 | 443 | 46.63 |
| Current smoker | 6,046 | 7.34 | 3,947 | 6.31 | 70 | 7.37 |
| Hormone Therapy Use | ||||||
| Never used | 37,413 | 44.95 | 26,774 | 42.27 | 397 | 41.40 |
| Past user | 12,221 | 14.68 | 10,979 | 17.33 | 161 | 16.79 |
| Current user | 33,593 | 40.36 | 25,589 | 40.40 | 401 | 41.81 |
| Osteoporosis Medications Use | ||||||
| No | 81,787 | 98.19 | 61,653 | 97.24 | 892 | 92.92 |
| Yes | 1,508 | 1.81 | 1,749 | 2.76 | 68 | 7.08 |
| Thiazolidinediones Use | ||||||
| No | 83,240 | 99.93 | 63,339 | 99.90 | 958 | 99.79 |
| Yes | 55 | 0.07 | 63 | 0.10 | 2 | 0.21 |
| Previous Joint Replacement | ||||||
| No | 77,918 | 99.20 | 58,604 | 93.29 | 773 | 81.28 |
| Yes | 628 | 0.80 | 4,218 | 6.71 | 178 | 18.72 |
OA: Osteoarthritis
RA: Rheumatoid arthritis
*
all variables significantly different between the three groups at p<0.001, with the exception of thiazolidinediones (p=0.020)