Table 4.
Bivariate and multivariable regression testing of association between patient case or control status and the results of the Faine’s criteria part A and part B score before and after adjustment for other variables, CaledoFaine study, New Caledonia, 2018 to 2019
| Variable category | Control subjects, n | Cases, n | P value* | Unadjusted odds ratio | Adjusted odds ratio in final model | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Estimate | 95% CI | P value | Estimate | 95% CI | P value | |||||
| MF A + B† | ||||||||||
| Leptospirosis unlikely | 61 | 3 | < 0.001 | 1.0 (Ref.) | – | – | 1.0 (Ref.) | – | – | |
| Leptospirosis possible | 8 | 10 | – | 25.41 | 5.75–112.31 | < 0.001 | 67.24 | 2.04 – 2,214.47 | 0.02 | |
| Leptospirosis presumed | 1 | 22 | – | 447.33 | 44.18–4,529.51 | < 0.001 | 148,426.9 | 1.54–1.4 × 1010 | 0.04 | |
| Leptospirosis possible or presumed | 9 | 32 | < 0.001 | 72.30 | 18.28–285.91 | < 0.001 | 379.18 | 15.29–9,405.54 | < 0.001 | |
| Continuous | 45.3 (30–61.2) | 43.5 (33.6–56) | 0.66 | 0.99 | 0.96–1.01 | 0.55 | – | – | – | |
| Province of residence | ||||||||||
| South | 57 | 19 | < 0.001 | 1.0 (Ref.) | – | – | 1.0 (Ref.) | – | – | |
| North | 6 | 13 | – | 6.50 | 2.17–19.48 | 0.001 | 7.01 | 0.42–115.86 | 0.17 | |
| Islands | 6 | 0 | – | – | – | – | – | – | – | |
| Year | ||||||||||
| 2018 | 31 | 25 | 0.013 | 1.0 (Ref.) | – | – | 1.0 (Ref.) | – | – | |
| 2019 | 38 | 10 | – | 0.33 | 0.14–0.78 | 0.012 | 0.19 | 0.014–2.46 | 0.22 | |
| Month | 0.38 | 0.13–1.10 | – | |||||||
| January | 13 | 4 | 0.001 | 1.0 (Ref.) | – | – | 1.0 (Ref.) | – | – | |
| February | 8 | 3 | – | 1.22 | 0.21–6.92 | 0.823 | – | – | – | |
| March | 17 | 14 | – | 2.68 | 0.71–10.07 | 0.145 | 8.26 | 0.01–2.46 | 0.97 | |
| April | 1 | 3 | – | 9.75 | 0.78–121.83 | 0.077 | 0.84 | 0.05–14.14 | 0.05 | |
| May | 0 | 0 | – | – | – | – | – | – | – | |
| June | 0 | 2 | – | Collinearity | – | – | – | – | – | |
| July | 0 | 3 | – | Collinearity | – | – | – | – | – | |
| August | 5 | 4 | – | 2.6 | 0.46–14.63 | 0.278 | – | – | – | |
| September | 3 | 2 | – | 2.17 | 0.26–17.89 | 0.473 | – | – | – | |
| October | 3 | 0 | – | Collinearity | – | – | – | – | – | |
| November | 10 | 0 | – | Collinearity | – | – | – | – | – | |
| December | 8 | 0 | – | Collinearity | – | – | – | – | – | |
| Oceanians of non-European or non-Asian ancestry | ||||||||||
| No | 38 | 26 | 0.058 | 1.0 (Ref.) | – | – | 1.0 (Ref.) | – | – | |
| Yes | 32 | 9 | – | 2.43 | 1.0–5.94 | 0.051 | 1.42 | 0.10–20.79 | 0.80 | |
| Time lapse since signs onset, Faine | ||||||||||
| Continuous | 2 (1–3) | 3 (2–5) | 0.002 | 1.42 | 1.12–1.80 | 3 | 2.25 | 0.99–5.10 | 0.17 | |
| 0–3 d | 52 | 18 | – | 1.0 (Ref.) | – | – | – | – | – | |
| 4–7 d | 12 | 15 | – | 3.37 | 1.38–8.17 | 0.007 | – | – | – | |
| CRP (mg/L) | ||||||||||
| Continuous | 56 (17–187) | 235 (177–334) | < 0.001 | 1.01 | 1.0–1.01 | < 0.001 | 1.23 | 0.93–1.63 | 0.15 | |
| < 10 | 7 | 0 | 0 | 1.0 (Ref.) | – | – | – | – | – | |
| 10–39 | 21 | 1 | – | 0.041 | 0.05–0.331 | – | – | – | – | |
| 40–79 | 6 | 0 | – | Collinearity | – | – | – | – | – | |
| ≥ 80 | 29 | 33 | – | Collinearity | – | – | – | – | – | |
| CRP > 30 and leptospirosis presumed or possible | ||||||||||
| No | 64 | 3 | < 0.001 | 1.0 (Ref.) | – | – | 1.0 (Ref.) | – | – | |
| Yes | 6 | 32 | – | 113.78 | 26.70–484.76 | < 0.001 | 104.81 | 13.31–825.10 | < 0.001 | |
A = part A; B = part B; CRP = C-reactive protein; MF = modified Faine.
*
Fisher test for qualitative variables; Wilcoxon test for continuous variables.
†
For Faine’s modified A + B criteria only: leptospirosis presumed if A score ≥ 26 or A + B score ≥ 25, leptospirosis possible if score between 20 and 25, and leptospirosis unlikely if score < 20.