Table 3.
Incidence Rates (IR) and incidence rate ratios (IRR) of serious infections in children with systemic lupus erythematosus and lupus nephritis, stratified by sociodemographics, among children enrolled in Medicaid, 2000–2006
| Systemic Lupus Erythematosus (SLE) N = 3,500 |
Lupus Nephritis (LN) N = 1,297 |
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|---|---|---|---|---|
|
| ||||
| IR | IRR (95% CI) | IR | IRR (95% CI) | |
|
| ||||
| Age | ||||
| 5 – <9 years | 7.9111.39 | ref | 15.95 | ref |
| 9 – <12 years | 10.00 | 1.44 (1.03, 2.02) | 19.36 | 1.21 (0.75, 1.96) |
| 12 – <15 years | 10.70 | 1.26 (0.92, 1.75) | 17.03 | 1.07 (0.68, 1.68) |
| 15 – <18 years | 10.79 | 1.35 (0.99, 1.86) | 17.74 | 1.11 (0.71, 1.73) |
|
| ||||
| Sex | ||||
| Female | 8.50 | ref | 18.69 | ref |
| Male | 6.86 | 0.79 (0.66, 0.95) | 12.76 | 0.68 (0.52, 0.90) |
|
| ||||
| Race/Ethnicity a | ||||
| White | ref | 12.01 | ref | |
| African American | 12.56 | 1.83 (1.51, 2.22) | 20.52 | 1.71 (1.23, 2.36) |
| Asian | 6.86 | 1.00 (0.73, 1.37) | 11.00 | 0.92 (0.58, 1.45) |
| Native American | 12.39 | 1.81 (1.17, 2.80) | 17.00 | 1.42 (0.72, 2.77) |
| Hispanic | 9.46 | 1.38 (1.11, 1.71) | 17.27 | 1.44 (1.01, 2.04) |
|
| ||||
| Region of residence | ||||
| NorthEast | 9.47 | ref | 17.90 | ref |
| South | 11.09 | 1.17 (0.98, 1.40) | 19.07 | 1.07 (0.84, 1.36) |
| West | 8.77 | 0.93 (0.76, 1.13) | 13.85 | 0.77 (0.58, 1.03) |
| MidWest | 12.42 | 1.31 (1.07, 1.61) | 20.19 | 1.13 (0.84, 1.52) |
|
| ||||
| SLE Risk Adjustment Index b | ||||
| Low | 7.11 | ref | 14.20 | ref |
| High | 15.68 | 2.21 (1.95, 2.50) | 28.26 | 1.99 (1.66, 2.39) |
|
| ||||
| Socioeconomic status c | ||||
| High | 10.70 | ref | 17.29 | ref |
| Low | 10.12 | 0.95 (0.83, 1.07) | 17.99 | 0.96 (0.80, 1.15) |
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| Preventive care use d | ||||
| Prophylaxis | 13.78 | 1.39 (1.16, 1.65) | 21.62 | 1.28 (1.02,1.61) |
| Influenza vaccination | 9.44 | 0.92 (0.58, 1.48) | 19.28 | 1.07 (0.60, 1.88) |
| Pneumococcal vaccination | 3.95 | 0.37 (0.11, 1.19) | — | — |
Incidence rates (IR) are reported per 100 person years (PY).
Bolded IRRs indicated statistically significant (p<0.05) values
4.7% of children with SLE had missing or other race reported
SLE Risk Adjustment index (median value in cohort is threshold for high vs. low)(17)
Socioeconomic status based on 7 zip-code level indicators from 2000 U.S. Census ((Z-scored, range −3.82 [lowest] to 6.06 [highest])(16)
Preventive care during the 6 month baseline period
— Cell counts of 10 or fewer individuals have been suppressed due to Federal reporting requirements.