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Background: The mortality rate of neonatal tetanus (NNT) remains high in Nigeria. The study was guided by Mosley and Chen’s model for the elements of child survival in developing countries. The goal of the study was to assess the associations between selected NNT risk factors, number of maternal tetanus toxoid injections, frequency of antenatal visits, place of delivery, and cord care with neonatal mortality as the outcome variable. Methods: The study is a retrospective record review using data from 332 NNT records and analyzed using a logistic regression model. Findings: Neonates whose mothers had 1 dose of tetanus toxoid vaccine were found to be 4% less prone to NNT mortality compared to neonates whose mothers did not have any dose of tetanus toxoid vaccine during pregnancy (P <.05, odds ratio = 4.12, 95% confidence interval = 1.04-16.29. Frequency of antenatal visits, place of delivery, and cord care were all not significant predictors of NNT mortality. Conclusion: The study shows that there is association between NNT risk factors and neonatal mortality, hence the need to further strengthen the NNT surveillance system for early detection of potential risk factors. This would help develop specific public health interventions aimed at improving the outcome of NNT. Implications: The identification and analysis of NNT mortality risk factors and promoting tetanus toxoid vaccination among pregnant women are effective strategies toward attaining NNT elimination goals in Nigeria.
The study was a cross-sectional survey of NNT Integrated Disease Surveillance and Response (IDSR) surveillance data and health facility retrospective record review from January 1, 2010, to December 31, 2014. A cross-sectional approach was utilized in this study because it provides a rapid assessment of the prevalence of a disease in a target population. 28 Cross-sectional surveys are also used to examine the associations between risk factors and variables of interest. Information was extracted by trained nurses as data abstractors and experienced physicians as medical reviewers from the 3 geopolitical zones (constituencies) of Katsina State, Nigeria. Access to both NNT IDSR data and health facility records was gained with the permission of Katsina State Ministry of Health. The NNT IDSR data included NNT cases confirmed based on the WHO case definition of NNT as any newborn who could suckle normally in the first 2 days of life but was unable to suckle between the 3rd and 28th days and has muscles spams or becomes stiff during the period of illness. 29 The data abstractors also screened for double reporting of NNT cases in both IDSR and health facility records. Double reporting occurs when an NNT case is counted twice before the final prevalence rate was calculated. The study aimed to identify whether or not associations existed between proximate factors and neonatal death using a binary logistic regression model. Data were analyzed using SPSS version 24. The proximate factors represented the independent variables, namely: (a) number of tetanus toxoid injections received by mothers, (b) the frequency of ANC visits attended by mothers, (c) place of delivery, and (d) cord care provided after delivery. Neonatal mortality represented the dependent variable, which was defined as death of newborn within the first 28 days of life. 29 Both independent and dependent variables were extracted from retrospective record review of NNT health facility records. Figure 1 depicts the association between the 5 constructs. Model of hypothesized association between 5 constructs in the study. ANC indicates antenatal care. Retrospective record review of health facilities was considered as the appropriate approach for this study because it could determine the prevalence and risk factors for health events. 30 Figure 2 depicts the retrospective review process in the study. Active surveillance retrospective record review process used in the study. At the first stage of the review process, data abstractors extract information on the prevalence of NNT and NNT mortality from the IDSR database of each health facility. Secondly, the data extractors will also screen for information on the prevalence of NNT, NNT mortality, and double reporting of NNT from health facility records and IDSR line list. The second stage of the review process is the verification of positively screened data by medical reviewers. The medical reviewers will verify information on NNT mortality and proximate factors. Adapted from Zegers et al. 31 Reproduced with permission. NNT indicates neonatal tetanus. Due to limited time and resources, multistage sampling technique was utilized to draw samples from each level of health care, that is, primary, secondary, and tertiary, in each of the 3 geopolitical zones in the state. The study sample consisted of 332 records of mothers of patients with NNT that were predetermined by 3 steps: (1) setting precision and statistical power, (2) calculating effective sample size using power analysis, and (3) sample size adjustment using design effect. 32 In the first step, the level of precision or α level was set at .05 so as to have a 5% chance of rejecting type I error. The statistical power was set at 95% to show that, with the sample size, the study can expect mean association between the proximate factors and neonatal death in 95% of the time. In the second step, effective sample size of 166 was realized following power analysis. However, the effective sample size was adjusted so as to account for the variance caused by multistage sampling technique. To adjust for deviation from simple random sampling, the effective sample size was multiplied by the design effect (DEFF). 33 In this study, the design effect was determined from a previous tetanus survey by Orimadegun et al, 34 who used a design effect factor of 2 to estimate the sample size required for a tetanus prevalence survey in Nigeria. Thus, sample size (N) = effective sample size × design effect (DEFF), which is 332. The study population comprised mothers of newborns affected with NNT in Katsina State, Nigeria. The sample size for this study was realized through multistaged sampling technique so as to obtain a representative sample of participants from each of the 3 zones in the state. The multistage sampling technique was conducted in 3 stages that include: (1) Selection of local government areas (LGAs) through random sampling and the LGAs selected were Katsina LGA, Malumfashi LGA, and Daura LGA from Katsina, Funtua, and Daura zones, respectively. (2) Selection of health facilities from the 3 levels of health delivery, that is, tertiary, secondary, and primary levels. The health facilities were sampled using random number of tables and those selected include General Hospital, Malumfashi (secondary) and Primary Health Center, Malumfashi (primary) in Malumfashi LGA; General Hospital, Daura (secondary) and Primary Health Centre, Dan Nakola (primary) in Daura LGA; and Federal Medical Center, Katsina (tertiary), General Hospital, Katsina (secondary), and Primary Health Center, Kofar Guga (primary) in Katsina LGA. (3) The 332 records of the study population were selected through proportional probability sampling (PPS) technique due to the variations in the amount of patients with NNT admitted in the health centers, as depicted in Figure 3. Participant flowchart. The NNT records reviewed for the study were selected from the positively screened records using proportional probability sampling. NNT indicates neonatal tetanus. An estimated 30 randomly selected NNT cases were tested in the pilot study at General Hospital, Dutsin-Ma, Katsina zone, Katsina State; these selected NNT cases were not be included in the larger study. It was conducted to assess the reliability and validity of instruments of data collection and to avoid missing data which is major challenge in retrospective record reviews. 30 The pilot study also enables the data abstractors to be more aware of inclusion and exclusion criteria and identification of certain challenges with the use of survey instruments. The inclusion criteria were: (1) only infants born within the neonatal period, that is, first 28 days of life; (2) all cases that had met the WHO case definition NNT; (3) all NNT cases treated in health facilities; and (4) all NNT cases treated from January 01, 2010, to December 31, 2015. The exclusion criteria were: (1) all infants born outside the neonatal period, that is, above 28 days old; (2) all cases that have not met the WHO criteria for NNT; (3) all NNT cases treated at home; and (4) all NNT cases treated prior to January 01, 2010, or after December 31, 2014. Forms A, B, and C were the instruments of data collection for the study. Form A was used to extract NNT prevalence and mortality data from the IDSR database in the 7 selected health facilities in Katsina State. The form was adapted from the WHO Death Investigation Form developed in 2002. 29 The format of the form was modified for the abstraction of NNT prevalence and mortality rates in this study. The original instrument was used by Cotter et al 35 for the evaluation of NNT elimination in Zimbabwe. Permission to modify and utilize the instrument for this study was sought from the Department of Vaccines and Biologicals, WHO, Geneva, Switzerland. Forms B and C were utilized by data abstractors and medical reviewers, respectively. Both forms are modified versions of RF1 and RF2 developed by the WHO Patient Safety Working Group for the review of harmful incidents in resource poor settings. 35 The forms are appropriate specifically for retrospective record reviews and were used in 2005 by the WHO for the retrospective review of harmful incidences among 18 146 randomly selected patients in 5 African countries, namely, Egypt, Kenya, South Africa, Sudan, and Tunisia. 36 This study examined the associations between the number of tetanus toxoid injections, frequency of ANC visits, place of delivery, and cord with NNT mortality using bivariate logistic regression model including adjusted odds ratios (ORs) and related 95% confidence intervals (95% CIs).
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