Table 4. Early predictors of laboratory-confirmed chikungunya versus all other acute febrile illnesses or laboratory-confirmed dengue for participants of all ages, Acute Febrile Illness Study, May 7, 2012–May 6, 2015, Puerto Rico.
| Predictors | Chikungunya N = 1,326 |
All Other AFI N = 4,892 |
aRR* (95% CI) | Dengue N = 281 |
aRR* (95% CI) | |||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | |||
| Positive Predictors | ||||||||
| Joint pain | 1088 | 85.1 | 1844 | 37.7 | 2.26 (1.79–2.85) | 140 | 49.8 | 1.26 (1.06–1.50) |
| Muscle, bone or back pain | 1133 | 85.4 | 2422 | 49.5 | 1.35 (1.05–1.75) | - | - | - |
| Red swollen joints | 565 | 42.6 | - | - | - | 20 | 7.1 | 1.13 (1.01–1.28) |
| Negative Predictors | ||||||||
| Thrombocytopenia | 23 | 1.7 | 131 | 2.7 | 0.53 (0.36–0.79) | 42 | 14.9 | 0.60 (0.38–0.93) |
| Cough | 331 | 25.0 | 2842 | 58.1 | 0.60 (0.52–0.69) | - | - | - |
| Sore throat | 279 | 21.0 | 1969 | 40.2 | 0.71 (0.61–0.82) | - | - | - |
| Rhinorrhea | 351 | 26.5 | 2661 | 54.4 | 0.72 (0.63–0.83) | - | - | - |
| Leukopenia | 221 | 16.7 | - | - | - | 166 | 59.1 | 0.73 (0.63–0.84) |
| Signs of poor circulation† | 405 | 30.5 | 1688 | 34.5 | 0.82 (0.72–0.92) | - | - | - |
| Abdominal pain | 403 | 30.4 | 1927 | 39.4 | 0.84 (0.74–0.97) | - | - | - |
| Diarrhea | 207 | 15.6 | 1133 | 23.2 | 0.85 (0.73–0.99) | - | - | - |
| Nausea | 549 | 41.4 | 2299 | 47.0 | 0.87 (0.77–0.99) | 165 | 58.7 | 0.88 (0.78–0.98) |
| Anorexia | 725 | 54.7 | 3088 | 63.1 | 0.88 (0.78–0.99) | - | - | - |
*Adjusted relative risk (aRR) based on pooled Poisson regression model.
(-) Indicates no significant predictor between chikungunya and comparator group.
† Signs of poor circulation included report of pale cold skin and/or having cyanosis.