Table 2.
Incidence correction factors for northern Nigeria CMAM program 2014 and 2015 and the data used to calculate them
| Year | ||||
|---|---|---|---|---|
| 2014 | 2015 | Data sources | ||
| Population | N | 3,550,827 | 4,281,700 | Nigeria census 2006 corrected for population growth and migration. Population is for children aged between 6 and 59 months in districts in which CMAM services were delivered. |
| Prevalencea | P | 1.60% (0.50%; 2.71%) | 2.01% (0.82%; 3.19%) | Pooled prevalence from state level SMART surveys |
| Program Coverageb | C | 36.6% (32.3%; 40.9%) | 36.6% (32.3%; 40.9%) | Wide-area SLEAC survey |
| Observed caseload | L | 320,047 | 398,676 | Routine program monitoring data |
| Expected caseload (using K = 1.6) | E K = 1.6 = CNP(1 + K) | 54,063 | 81,897 | C, N, and P as above (C and P expressed as proportions). Calculations are based on K = 1.6 |
| Difference (observed − expected) | L − E K = 1.6 | 265,984 | 316,779 | Calculated as the difference between observed caseload (L) and expected caseload (E). |
| Prevalence × Coverage | PC | 0.59% (0.29%; 1.18%) | 0.74% (0.40%; 1.34%) | Calculated (see text) |
| Incidence correction factorc | 14.39 (6.64; 30.02) | 11.66 (5.94; 22.10) | Calculated (see text) | |
| Expected caseload (using pooled adjusted incidence correction factor) | E K = 13.02 = CNP(1 + K) | 291,527 | 441,612 | C, N, and P as above (C and P expressed as proportions). Calculations are based on K = 13.02 (see text). |
| Difference (observed − expected) | L − E K = 13.02 | 28,520 | −42,936 | Calculated as the difference between observed caseload (L) and expected caseload (E K = 13.02). |
aPrevalence is for MUAC <115 mm or bilateral pitting edema. This case-definition accounts for c. 98% of all program admissions based on an analysis of routine program monitoring data from two states of northern Nigeria (n = 102,245 admissions from January 2010 to December 2013). Prevalence estimates for the states in which the program was operating are reported. This was calculated as the population weighted average of SMART survey results from individual states
bCoverage refers to point coverage (i.e. the proportion of current SAM cases found by the survey that were enrolled in the CMAM program). Results from a wide-area SLEAC survey from February 2014 are used for both years [Banda et al., 2014]
cThe formula of the estimator for K is rearranged to reflect the fact that PC was calculated prior to use