Data sources

The under-five and diarrhea-specific mortality data was obtained from the United Nations Inter Agency Group for Mortality Estimation (IGME) and World Health Organisation-Maternal and Child Epidemiology Estimation (MCEE) group [1,9,10]. Information on policies and programs concerning diarrhea case management, poverty reduction, health system changes, social protection schemes and scale up of intersectoral strategies to improve nutrition, access to safe drinking water and sanitation were obtained from the reports and websites of relevant ministries of the Government of India [11-19]. The intervention coverage data was sourced from the National Family and Health Surveys (NFHS) and Joint Monitoring Programme reports [20-22].

Statistical analysis

The Lives Saved Tool (LiST) was used to estimate the attribution of the factors, individually and as packages, in reduction of diarrhea mortality and the number of lives saved from 1980 to 2015 [6,7,23]. The LiST modelling approach is based on change in coverage of an intervention over a specified period, its efficacy (on diarrhea specific under-five mortality), and the affected fraction (the proportion of the outcome that is amenable to treatment with the given intervention).

Coverage change × Effectiveness × Affected fraction = Impact [23]

For changes in risk factors such as stunting or wasting, their relative risk or odds ratio for cause-specific mortality are included in the model. Detailed description of the various linkages in LiST related to diarrhea mortality as well as the efficacy used in the model are described elsewhere [6,8]. Analysis were performed for the period 1980 to 2015 and for sub-periods, 1980-2000 and 2000-2015, representing time windows pre and post attention to achieving the Millennium Development Goals (MDG).

The year 1980 was considered as baseline for coverage data of all interventions. In case of non-availability, linear interpolation using the available estimate closest to 1980 was done to generate data, considering 1960 as the year of introduction for interventions that were available in 1980. For interventions introduced in the public sector after 1980, the year prior to introduction was considered to have zero coverage. Intervention coverage for 2015 was estimated using the most recent data source available. To obtain coverage data for the year 2000, linear interpolation was done using data of the earliest and latest measured time points. The details of the data sources area presented in the online supplementary document (Table S1 in Online Supplementary Document)

A predictive analysis was performed to estimate the potential impact of scaling up varied intervention packages by 2030. To guide future strategies for prevention of residual diarrhea mortality and, the potential number of lives that can be saved by upscaling different intervention packages from the coverage levels in 2015 to universal coverage levels (90%) by 2030 was explored using three scenarios. For stunting and wasting the World Health Assembly targets ie, 50% reduction in number of children stunted and wasting prevalence of <5% were used [24].

The different scenarios are as follows: Interventions in scenario 1 are related to diarrhea case management, specifically oral rehydration salt solution and zinc for all, antibiotics for dysentery and rotavirus vaccination. In scenario 2, improvement in vitamin A coverage, stunting, wasting and breastfeeding practices were additionally included and in scenario 3, Water, sanitation and hygiene (WASH) interventions ie, hand-washing with soap and combined improved sanitation and water source were added to the package in scenario 2.

Diarrhea specific mortality rate (DSMR) reduction in under-five children in India

The under-five DSMR declined from 33.9 in 1980 to 4.7 per 1000 live births in 2015; using changes in coverage and risk factors the LiST model explains 67% of this decline [10,25]. The proportion of total under-five mortality due to diarrhea declined from 20% to 10% in the same period (Figure 1).

Figure 1.  Diarrhea mortality trends in India, 1980-2015.

The average annual rate of reduction in under-five diarrhea mortality per 1000 live births progressively increased from 1% to 4% between 1980 and 2014; this rate peaked post 2005 (Figure 2). However, the prevalence rate, based on two-week recall in national surveys, of diarrhea remained static at around 9% from 2005 to 2015 [20,21].

Figure 2.  Annual rate of reduction of under-five diarrhea mortality in India, 1980-2015. CDD – Diarrhea Disease Control Programme, ORS – oral rehydration salt solution, CSRP – Central Rural Sanitation Program, IMS – infant milk substitute act, BFHI – Baby Friendly Hospital Initiative, TSC – Total Sanitation Programme, MDGs - Millennium Development Goals, IMNCI – Integrated Management of Childhood and Neonatal Illness, NRHM – National Rural Health Mission, ASHA – Accredited Social Health Activist, MGNREGA – Mahatma Gandhi National Rural Employment Guarantee Act, iCCM – integrated Community Case Management, IDCF – Intensified Diarrhea Control Fortnight [12-14,17,19,26-30].

Change in coverage of drivers of DSMR reduction in India

The decline in under-five diarrhea mortality coincided with the pace of economic growth in the country during the last two decades. The GDP per capita of India increased more than 5-fold from US$263 in 1980 to US$1613 in 2015 [31]; the magnitude of increase was greater in the post-2000 period. The proportion of population living below poverty line declined from 54% in 1983 to 21% in 2011 [32].

Data on the coverage of case management interventions, rates of wasting, stunting and access to water and sanitation are described in Table 1. ORS use rate during diarrhea doubled from 26% in 2005-06 (NFHS 3) to 51% in 2015-16 (NFHS 4) [20,21]. The change in ORS use rates varied by state, setting and wealth quintiles. ORS use rates were greater than 50% in three states in 2005-06 compared to 19 states in 2015-16. The ORS use in urban populations increased from 33% to 44% and that in the rural areas from 24% to 37% during this period. The increase of ORS use ranged from 18 percentage points to 29 percentage points among the different wealth quintiles and increased by 25 percentage points in the lowest wealth quintile (Figure 3). Zinc was introduced in 2007 for diarrhea case management [33]. Use of zinc for diarrhea treatment was 20% at national level, ranging from 13% to 58% across different states in the most recent national survey [20]. Rotavirus vaccine was introduced in the national immunization schedule in 2016 in 4 states and is being rapidly scaled to other states [34], thus could not be included in the 1980-2015 analysis but could be in the projections to 2030.

Figure 3.  Increase in oral rehydration salt solution (ORS) use rates between NFHS-3 and NFHS-4 by wealth quintiles in India.

There were significant improvements in nutrition related indicators in under-five children between NFHS 3 and 4. Vitamin A supplementation coverage increased from 17% to 60%, exclusive breastfeeding in first six months increased from 46% to 55%, stunting (height-for-age<-2 SD) decreased from 48% to 38%. There was a marginal increase in the proportion wasted from 20% to 21%. Households with access to an improved sanitation facility increased from 29% to 48%.

Policies and Programs influencing DSMR reduction in India

The key policies and programs that may have influenced the rate of reduction of diarrheal mortality from 1980 to 2015 are shown in Figure 2 and online supplementary document (Table S2 in Online Supplementary Document). The diarrhea control program was initiated as a vertical program in the 1980s under the effective stewardship of the Ministry of Health and Family Welfare with support from international partners including WHO and UNICEF [26]. The management of persistent diarrhea was later incorporated in the program, as it contributed to around 25% to the overall diarrhea mortality [35]. In an effort to achieve greater integration of maternal and child health interventions, diarrhea case management was incorporated as a component of the Child Survival and Safe Motherhood (CSSM) and subsequently into Reproductive and Child Health (RCH-I and RCH-II) programs [18,36,37]. Though these programs had more funding and improved management systems, integration into these broad-based programs attenuated the focus on diarrhea. Integrated Management of Neonatal and Childhood Illness (IMNCI) was introduced in 2003 for better management of common childhood illnesses and diarrhea case management became a part of IMNCI [17]. The initial scale-up and quality of practice of IMNCI was slow. The ORS supplies did not reach the periphery given the facility-based treatment focus. Subsequently, social marketing of ORS, introduction of low osmolality ORS in 2005 and zinc in 2007 were the major changes in diarrhea case management in India. The antibiotic policy for treatment of dysentery was changed to ciprofloxacin/ceftriaxone as resistance to co-trimoxazole became common [38].

The introduction of one million grass root level health workers called ASHA (Accredited Social Health Activist) was a major reform in the health system of the country under the National Health Mission in 2005 [39]. The focus then shifted to diarrhea and pneumonia treatment under integrated community case management (iCCM) [27,28]. ORS availability increased at community level through ASHA workers. Since 2014, a further boost was provided though initiation of intensified diarrhea control fortnight [29], as every family with under-five children were visited by ASHAs and delivered a packet of ORS, zinc tablets and counselling message. The diarrhea case management is now an integrated community-based program with facility linkage for management of severe cases [40].

Relevant interventions targeted at poverty reduction (The Mahatma Gandhi National Rural Employment Guarantee Scheme, 2006) and social protection for health care access (Rhastriya Swasthya Bima Yojana, 2008) were implemented across the country [11,13]. Sanitation has received major attention under Total Sanitation Campaign, earlier and now under “Swachh Bharat Mission, 2014” [12,15,16].

LiST estimates for contribution of factors to DSMR reduction

The number of lives saved and the percentage of DSMR reduction in under-five children attributable to each factor for the periods 1980-2015, 1980-2000 and 2000-2015 are shown in Table 2. In comparison to 1980, over 0.66 million under-five diarrheal deaths were averted in 2015 as a combined effect of different factors. The major factors associated with DSMR reduction in under-fives were ORS use, reduction in stunting prevalence, sanitation, age appropriate breastfeeding practices, vitamin-A supplementation and treatment of persistent diarrhea. ORS use and reduction in stunting were the two key factors, each accounting for around 32% of the lives saved during 1980 to 2015. In the earlier period ie, comparing 1980 to 2000, improvements in nutrition made a higher contribution to DSMR reduction compared to diarrhea case management and WASH interventions. Whereas post-2000, diarrhea case management interventions were the major drivers for DSMR reduction (Figure 4).

Figure 4.  The contribution of WASH, nutritional and direct diarrhea interventions to under-five diarrhea specific mortality reduction for the time periods 1980-2015, 1980-2000 and 2000-2015.

LiST projections for number of lives saved attributable to scaling up different intervention packages

The projected number of lives saved and DSMR reduction in under-fives attributable to scaling up of different intervention packages for the three scenarios by 2030 are presented in Table 3. Our estimates show that scaling up of the direct diarrhea case management interventions (scenario 1) alone can avert around 82000 under-five diarrheal deaths in 2030; ORS use being the major contributor (51%). In addition, if the targets for nutritional parameters are also met around 20 000 additional under-five diarrheal deaths could be averted in 2030 (scenario 2). Incorporating WASH interventions to the above package will save another 3000 lives (scenario 3). Viewed another way, scaling up of the interventions packages to attain near universal (90%) coverage levels by 2030, can reduce under-five diarrhea mortality rate by 73%, 91% and 94%, for the three scenarios, respectively.