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This household survey was conducted as part of a larger study to identify and quantify the major barriers to the scale up and use of interventions to control malaria in pregnancy at the district, facility, and community level. The study was conducted in Greater Nyando District (now divided into Nyando, Muhoroni and Nyakach districts) in Nyanza Province, Kenya, between February and March 2010. Greater Nyando District has a population of 355,800 (1999 census), with more than 90% living in rural areas. Malaria is perennial holo-endemic with a parasite prevalence of 8.3% among women of child bearing age (2008 unpublished data, KEMRI/CDC), peaking between April to June and October to December. HIV prevalence among women aged 15–49 years is higher in Nyanza Province compared to all other provinces in the country, 18% compared to national average of 9% [24]. Greater Nyando had a total of 40 health facilities of which 60% (24) were owned by government, 13% (5) by missions, 18% (7) privately owned and 10% (4) community run. The government facilities comprised 1 hospital, 2 sub-district hospitals, 6 health centres and 15 dispensaries, the mission owned 1 hospital, 3 health centres and 1 dispensary and the community owned 4 dispensaries. In line with WHO recommendations on focussed antenatal care (FANC), national policy in Kenya is for pregnant women to receive a package of interventions through antenatal care at each of 4 recommended ANC visits. Malaria in pregnancy interventions are delivered alongside prevention and control of mother to child transmission of HIV (PMTCT), tuberculosis, syphilis/sexually transmitted infections, palpations and birth planning. Malaria services include a free long-lasting insecticide treated net (LLIN) provided to all women at their first ANC visit, a minimum of two doses of SP taken under DOT and prompt diagnosis and treatment of malaria episodes with an effective antimalarial alongside health education at ANC [25]. According to current national guidelines, the first dose of SP should be given to all women after quickening and subsequent dose(s) taken at least 4 weeks (one month) apart. HIV positive pregnant women taking daily cotrimoxazole should not be given IPTp-SP [25], [26]. Kenya adopted IPTp policy in 1999, followed by the delivery of ITNs to pregnant women through ANC in 2001. National level DHS data available at the time the study was designed (DHS 2003) showed that 84% of women made two or more ANC visits, 4% pregnant women received two doses of SP during ANC visits and 4% of pregnant women used an ITN the night before the survey [24]. The IPTp and ITN coverage figures for Nyanza Province were marginally higher than the national average, with 5% reporting having received two doses of IPTp and 9% pregnant women reporting having used an ITN the night before the survey.
Study Design and Selection of Study Participants: A two stage cluster sampling household survey was undertaken over 3 weeks during a period of intense rains, between February and March 2010. Enumeration areas from the 1999 census were used to select 40 villages, representing clusters, using probability proportional to size. A sample size of 338 women of child-bearing age (15–49 years) was sufficient to estimate an IPTp or ITN uptake of 50%, with a 6% precision, design effect of 1.75 and 10% non-response. The sample size was increased to 1,120 to maintain precision in a range of intermediate processes in the delivery of IPTp and ITNs with decreasing sample size, where women are lost from the evaluable sample at different points [27], and uses the hypothetical assumptions that 60% of women attending ANC are offered an ITN, of which 50% then use the ITN. Households in selected clusters were mapped using Global Positioning System (GPS) software (CDC GPS Sample for Windows Mobile devices https://sites.google.com/a/wolkon.com/gps-sample/). Thirty five households were randomly selected from GPS coordinates of all households within each cluster to get 28 households with women of childbearing age as resident. One respondent within each household was selected using a set of predefined criteria as follows: women must be aged 15–49 years; pregnant women were prioritised over mothers of children aged under one year, who were prioritised over other eligible women; and if more than one eligible woman was currently pregnant/mother of a child aged under 1, the woman most closely related to the head of the household was interviewed (i.e. wife> daughter> sister> niece/aunt> daughter-in-law).
The questionnaire sought to obtain key coverage indicators on the frequency and timing of ANC attendance, the frequency, timing and source of IPTp-SP doses and whether each dose was taken under DOT, and whether an ITN was obtained, by source, and used during the current/most recent pregnancy; to understand women’s knowledge of malaria in pregnancy in relation to use of IPTp and ITNs; and to determine whether HIV status alters behaviour patterns. A composite malaria knowledge score was created based on the cumulative score of correct responses in relation to source of malaria (mosquitoes), consequences of malaria in pregnancy to mother (anaemia) and unborn child (miscarriage, low birth weight, premature birth, stillbirth) and of methods to prevent malaria in pregnancy (e.g. IPTp, nets and/or ITNs). HIV status was self-reported, and additional indirect questions about recognition and use of cotrimoxazole and history of episodes of opportunistic infections associated with HIV were included. Self-reported IPTp, ITN and ANC practices, including HIV testing and results, were compared with data contained in ANC cards where available. Recording of household assets to develop a wealth index and observation of household ITNs in situ was also performed. Principal components analysis was used to construct a wealth index to assess socio-economic status (SES) [28], [29] using household characteristics such as education of the household head, number of sleeping rooms, floor materials, source of drinking water, type of toilet facilities, household ownership and a range of household assets. The questionnaire was translated and back translated to ensure accuracy of translation of concepts and variables, and then pre-tested. Interviewers were trained to conduct the interviews in the two most commonly spoken local languages, Dholuo and Kiswahili.
The concept of intervention effectiveness as described by Vlassoff and Tanner showed how the translation of the efficacy of a disease control tool into community effectiveness was dependent on coverage, diagnostic accuracy and the compliance of users and providers [30]. More recently this concept has been adapted for delivery of interventions through the health system [21], and used as a health systems effectiveness framework by the malERA consultative group [33]. We adapted this concept specifically for the delivery of IPTp and ITNs through ANC to measure delivery system effectiveness using household data to identify critical points in the delivery system that were ineffective (Figure 1). We then explored the predictors of effectiveness at critical points of weakness identified in the delivery pathway.
Figure data removed from full text. Figure identifier and caption: 10.1371/journal.pone.0064913.g001 Algorithm for cumulative systems effectiveness of ANC, IPTp and ITN use.ANC: antenatal clinic; CTX: cotrimoxazole; SP: sulphadoxine-pyrimethamine; DOT: directly observed therapy; IPTp: intermittent preventive treatment; ITN: insecticide treated net. Data from the household surveys were collected on personal digital assistants (PDAs). All analyses were adjusted for the survey design, clustering of households and sample weights using STATA 11. Socio-demographic characteristics of pregnant and recently pregnant women were described and compared. Proportions of women accessing ANC, receiving each dose of SP by source and the timing of each dose, and receiving ITNs by source were quantified among both groups of women. The indicator for ITN use among pregnant women was the proportion of pregnant women who reported having used an ITN the night before the survey [34], [35], and for recently pregnant women the indicator used was the proportion of women who reported having used an ITN regularly during the most recent pregnancy [36], [37]. The systems effectiveness analysis was undertaken using recently pregnant women and excluded HIV positive women with documented use of cotrimoxazole. Systems effectiveness was defined as the proportion of women attending ANC who reported having received at least two doses of SP and used an ITN regularly during the most recent pregnancy. Two categories of effectiveness analyses were applied - ‘intermediate process effectiveness’ and ‘cumulative systems effectiveness’ [38]. Intermediate process effectiveness represents coverage of women at each of the intermediate steps in the delivery of IPTp, with the addition of ‘used any ITN’ and then ‘used an ITN from ANC’ together with taking the second dose of IPTp as the final process. Intermediate process effectiveness was calculated as the number of women who successfully completed the intermediate process (the numerator) as a proportion of all women who reached that point in the delivery system (the denominator) (see formula in Figure 2). An intermediate process was classified as ineffective if <80% women successfully completed that step. Cumulative systems effectiveness represents successful coverage of women for each of the intermediate steps up to that point in the delivery system. The final step represents the percent of eligible women in the community that received both interventions and is equivalent to a cumulative coverage indicator for several indicators (two ANC visits, two doses of SP (IPTp) and ITN use) that are measured by DHS.
Figure data removed from full text. Figure identifier and caption: 10.1371/journal.pone.0064913.g002 Formula for calculating intermediate and cumulative systems effectiveness.Where: N = Total number of target population; Nx = Number of women successfully completing step x IE: Intermediate effectiveness; CE: Cumulative effectiveness. Intermediate process effectiveness and cumulative systems effectiveness analyses for IPTp were performed on women receiving IPTp in an eligible month of gestation (4 to 9 months) and excluded women who did not receive IPTp and who were taking cotrimoxazole as documented on ANC cards as per national policy. This analysis was conducted under two scenarios, Scenario A where the criteria of receiving IPTp by DOT was not included, and Scenario B where women received IPTp by DOT i.e. per policy. The systems effectiveness analysis for ITNs was not restricted by gestational age as policy states ITNs are to be delivered to women at their first ANC visit regardless of gestation. Univariate analyses of potential predictors of receipt of: i) two doses of SP (with or without DOT); ii) one dose by DOT; and iii) two doses by DOT (as the three least effective processes identified in the effectiveness analysis), was conducted using logistic regression models accounting for survey design, and adjusted Wald tests were applied to test for associations between predictors and outcomes. We also explored the predictors of ITN use. Predictors explored included those known to be important from previous studies, including: selected individual and household socio-demographic factors (women’s age, marital status, education, malaria knowledge using the composite malaria knowledge score, urban: rural residence and SES); gravidity; having lost a live born child; number and timing of ANC visits; whether they recently had an episode of malaria and whether they took medicine for that episode. Variance inflation factors were examined for all predictors included in the models to assess potential collinearity. Potential predictors significant at the 10% level (p<0.1) in the univariate analyses were included in multivariable logistic regression models to determine which factors were associated with the outcomes after accounting for other potential predictors. Interactions between paired predictors were assessed for all predictors included in the models. We estimated the potential and actual effectiveness of the malaria in pregnancy prevention strategy on low birth weight (LBW) extrapolated to the pregnant population of Nyanza Province (n = 225,001). We used the protective efficacy of IPTp on LBW of 29% observed in a meta-analysis of trials which compared 2-dose IPTp with SP to case management or placebo in women during their first or second pregnancy (RR 0.71; 95% CI 0.55–0.92) [5], a prevalence of LBW of 12% (unpublished data from Siaya District Hospital, Ouma personal communication), and co-coverage with IPTp by DOT and ITNs, using the following formula [39]: The study was approved by the ethical committees of the Kenya Medical Research Institute (KEMRI) National Ethics Review Committee, the Liverpool School of Tropical Medicine, the London School of Hygiene and Tropical Medicine, and the US Centers for Disease Control and Prevention in Atlanta. Written informed consent was obtained from women prior to being interviewed at home and for adolescents, both parental permission and assent of the subject was obtained.
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