Performance of case definitions used for influenza surveillance among hospitalized patients in a rural area of India
Siddhivinayak Hirve, Mandeep Chadha, Pallavi Lele, Kathryn E Lafond, Avinash Deoshatwar, Somnath Sambhudas, Sanjay Juvekar, Anthony Mounts, Fatimah Dawood, Renu Lal & Akhilesh Mishra
Volume 90, Number 11, November 2012, 804-812
Table 3. Clinical predictors of influenza in hospitalized patients, Vadu, India, May 2009–April 2011
| Signs and symptoms, by patient age | No. of patients positive for influenza virus/no. tested (% positive) |
RR | P | |
|---|---|---|---|---|
| with symptom/sign | without symptom/sign | |||
| Patients aged < 5 years (n = 337) | ||||
| Symptoms | ||||
| Fever (reported) | 34/299 (11.4) | 5/24 (20.8) | 0.55 | 0.227 |
| Cough | 30/221 (13.6) | 9/101 (8.9) | 1.52 | 0.269 |
| Sore throat | 20/153 (13.1) | 19/170 (11.2) | 1.17 | 0.628 |
| Nasal discharge | 24/199 (12.1) | 15/124 (12.1) | 1.00 | 0.983 |
| Earache/discharge | 0/3 (0.0) | 39/320 (12.2) | – | 0.695 |
| Fast breathing | 4/43 (9.3) | 33/268 (12.3) | 0.76 | 0.634 |
| Lethargy | 0/6 (0.0) | 39/317 (12.3) | – | 0.481 |
| Inability/refusal to feed | 3/37 (8.1) | 36/285 (12.6) | 0.64 | 0.489 |
| Vomiting | 10/133 (7.5) | 29/190 (15.3) | 0.49 | 0.047 |
| Diarrhoea | 7/120 (5.8) | 32/203 (15.8) | 0.37 | 0.011 |
| Seizures | 1/11 (9.1) | 38/312 (12.2) | 0.75 | 0.874 |
| Signs | ||||
| Fever (> 38.0 °C) | 38/265 (14.3) | 5/64 (7.8) | 1.84 | 0.192 |
| Tachypneaa | 0/0 | 43/332 (13.0) | – | 1.000 |
| At least one IMCI danger signb | 5/56 (8.9) | 34/265 (12.8) | 0.70 | 0.469 |
| Patients aged ≥ 5 years (n = 2842) | ||||
| Symptoms | ||||
| Fever (reported) | 595/2732 (21.8) | 13/46 (28.3) | 0.77 | 0.352 |
| Chills/rigor | 550/2553 (21.5) | 68/274 (24.8) | 0.87 | 0.273 |
| Cough | 497/1791 (27.8) | 121/1036 (11.7) | 2.38 | 0.000 |
| Sore throat | 361/1162 (31.1) | 257/1664 (15.4) | 2.01 | 0.000 |
| Nasal discharge | 391/1243 (31.5) | 227/1584 (14.3) | 2.20 | 0.000 |
| Earache/discharge | 7/16 (43.8) | 609/2808 (21.7) | 2.01 | 0.090 |
| Headache | 532/2514 (21.2) | 86/313 (27.5) | 0.77 | 0.027 |
| Muscle aches | 452/2061 (21.9) | 166/766 (21.7) | 1.01 | 0.900 |
| Chest pain | 16/64 (25.0) | 602/2761 (21.8) | 1.15 | 0.572 |
| Shortness of breath | 23/78 (29.5) | 551/2317 (23.8) | 1.24 | 0.314 |
| Vomiting | 111/492 (22.6) | 507/2334 (21.7) | 1.04 | 0.711 |
| Diarrhoea | 42/225 (18.7) | 575/2601 (22.1) | 0.84 | 0.289 |
| Seizures | 0/8 (0.0) | 618/2819 (21.9) | – | 0.174 |
| Confusion | 0/4 (0.0) | 618/2822 (21.9) | – | 0.416 |
| Signs | ||||
| Fever (> 38.0 °C) | 488/2208 (22.1) | 123/585 (21.0) | 1.05 | 0.627 |
| Tachypneac | 574/2661 (21.6) | 41/157 (26.1) | 0.83 | 0.241 |
| Respiratory distressd | 8/47 (17.0) | 0/0 | – | 1.000 |
IMCI, Integrated Management of Childhood Illness; RR, relative risk.
a Defined as respiratory rates, in breaths per minute, of > 60, > 50 and > 40 for children aged < 2 months, 2–12 months and 1–4 years, respectively.
b Inability to drink or breastfeed, vomiting of everything, convulsions, lethargy/unconsciousness, chest in-drawing or stridor in a calm child.
c Defined as a respiratory rate of ≥ 20 breaths per minute.
d Defined as stridor, crepitation, wheeze or reduced air entry.