Sleman HDSS

Figure 1. Number of Sleman HDSS Respondents in Each Subdistrict

Sistem Surveilans Demografi dan Kesehatan (Health and Demographic Surveillance System/HDSS) is a surveillance system that collects population transition data, health status and social transition periodically within a certain period. In 2014, the Faculty of Medicine, Public Health, and Nursing, Gadjah Mada University (UGM) in collaboration with the Sleman Regency government initiated the implementation of HDSS in Sleman Regency called Sleman HDSS. Sleman HDSS is primary funded by the Faculty of Medicine, Public Health, and Nursing (FK-KMK), Universitas Gadjah Mada, Indonesia.

Sleman HDSS conducts data collection once a year with wave 1 data collection carried out in 2015. During 2015-2019, Sleman HDSS has carried out 5 waves of data collection. In the first wave, 5,147 selected households from 216 clusters (census blocks) in all sub-districts in Sleman Regency took part in Sleman HDSS. During the wave 1 (baseline survey) Sleman HDSS collected basic demographic data such as age, gender, education, occupation, health insurance ownership, births, and deaths.

In the second and subsequent waves, Sleman HDSS updated demographic data and collected other health-related data such as communicable and non-communicable diseases, behavioural risk factors, and health care services utilisation. Besides conducting health and demographic surveys, HDSS Sleman conducting several supporting activities such as community service, advocacy for the Sleman Regency government, as well as opening opportunities for researchers to conduct nested research, and opportunities to use HDSS data under applicable regulations.

Sleman HDSS’ vision is to “Support scientific development in the health sector through an innovative, excellent, and high-quality, world-class research based on population data”.

To achieve this vision, Sleman HDSS has set the following missions:

  1. Efficiently collecting high quality population-based longitudinal data.
  2. Supporting the sustainability of health research at UGM.
  3. Supporting education and training activities in the field of population-based longitudinal study.
  4. Encouraging health policies making based on scientific evidence.
  5. Supporting scientific evidence-based community service activities.

The objectives of Sleman HDSS are:

  1. Establishing a surveillance site to collect data on demographics, epidemiology, ecological factors (risk factors), and utilisation of health services.
  2. Building networks and partnerships in order to support independent and sustainable research.
  3. Producing quality demographic and health data as the basis for further research, evidence-based policymaking, community service, and educational activities.
  4. Organising activities that support education in the population-based longitudinal research field.
  5. Supporting the improvement of population health through evidence-based community service.

The Sleman HDSS Milestones are:

  • Establishing Sleman HDSS surveillance site.
  • Having national and international networks and partnerships.
  • Joining the international HDSS network.
  • Continuous implementation of Sleman HDSS.
  • Establishing an information system that supports the performance of data collection and management of Sleman HDSS.
  • Establishing a collaborative system through nested research, secondary data analysis, and community service schemes.
  • Establishing cooperation with the Sleman district government in evaluating and making policies based on research results (evidence-based policy-making).
  • Establishing a support system for student and other academic communities in of population-based longitudinal research field.
  • Establishing Sleman HDSS open data system.
  • Organising the collection of biological samples in the Sleman HDSS population.

Sleman HDSS is a prospective longitudinal survey involving a panel of households representing the population of Sleman Regency. Information on demographics and health is collected from these households in each wave. However, household members involved in HDSS Sleman are dynamic. This is because family members may move out of the HDSS household or pass away. In addition, family members who were born or individuals who moved into the HDSS household are considered as HDSS respondents.

The calculation of Sleman HDSS longitudinal survey sample size designs to estimate demographic and health conditions using the infant mortality rate as the main parameter. The infant mortality rate was measured using the Brass indicator (25.0/1000 live births in the Daerah Istimewa Yogyakarta Province). The sample size calculation also considers other aspects, including the proportion of under-five children (7.9%), the Sleman Regency average number of household members (3.3 in 2013), 95% confidence interval, precision, the margin of error (9%), the effect of the study design (2.0), the drop-out estimation (10%), and non-response rate (5%). Thus, the minimum sample size is 4942 households or rounded up to 5000 households.

Sleman HDSS respondents are residents who have resided or will reside in Sleman Regency for six consecutive months. The sample was selected using two-stage cluster sampling with probability proportionate to size.

  1. In the first stage, we randomly selected 216 clusters from 3513 clusters in Sleman Regency. The clusters were adjusted to the Sleman Regency urban-rural area proportions, 184 clusters in urban areas (85%) and 32 clusters (15%) in rural areas.
  2. In the second stage, systematic random sampling was conducted to select 25 households from each cluster. A total of 5,127 households participated in the Sleman HDSS wave 1.

In the baseline survey, Sleman HDSS successfully collected data from 19,724 residents in 5,147 households. They are spread across 216 clusters in all sub-districts in Sleman Regency. In wave 4 (2018), respondents who could not be visited in the three-wave data collection were replaced with new respondents (refreshment sample). The refreshment sample intends to readjust the number of Sleman HDSS samples to fulfil the minimum sample requirement.

A further explanation has described in this publication:

Dewi, FST., Choiriyyah, I., Indriyani, C., Wahab, Abdul., Lazuardi, Lutfan., Nugroho, Agung., et al. Designing and collecting data for a longitudinal study: the Sleman Health and Demographic Surveillance System (HDSS). Scandinavian Journal of Public Health 2018;46(7):704-710. https://doi.org/10.1177/1403494817717557

Ethical Clearance 

HDSS Sleman started operating after obtaining permission from the Committee for Medical and Health Research Ethics, Faculty of Medicine, Public Health and Nursing, UGM. Continuing review is conducted annually. The list of ethical reviews that have been carried out on HDSS Sleman can be seen in Table 1.

Table 1. List of ethical reviews conducted on Sleman HDSS

Release date Type Ethical clearance number
22 July 2014 Ethical clearance Wave 1 – 2015 KE/FK/842/EC
18 August 2015 Ethical clearance Wave 2 – 2016 KE/FK/1037/EC
27 April 2017 Ethical clearance Wave 3 – 2017 KE/FK/0492/EC/2017
04 May 2018 Ethical clearance Wave 4 – 2018 KE/FK/0434/EC/2018
10 May 2019 Ethical clearance Wave 5 – 2019 KE/FK/0526/EC/2019
15 May 2020 Ethical clearance Wave 6 – 2020 KE/FK/0586/EC/2020
11 June 2021 Ethical clearance Wave 7 – 2021 KE/FK/0640/EC/2021
13 June 2022 Ethical clearance Wave 8 – 2022 KE/FK/0641/EC/2022
12 June 2023 Ethical clearance Wave 9 – 2023 KE/FK/0961/EC/2023

Informed Consent

Prior to each data collection, HDSS Sleman respondents were asked for their consent to participate in the survey. Respondents are asked to sign an informed consent form after receiving information about HDSS Sleman and stating their willingness to participate.

Confidentiality

Sleman HDSS assures the confidentiality of respondent’s identity and data. Data released by Sleman HDSS has been processed so that it does not have any information that can be used to identify respondent personally.

Sleman HDSS data collection has been conducted once in a year since 2015. Data collection activities began with interviews for Sleman HDSS core modules which comprising demographic modules (e.g., new household member socio-demographic profile and updating socio-demographic profile of the existing household members), health-related modules (e.g., Infectious diseases, Non-communicable diseases, and health care service utilisation), and individual panel data collection (e.g., quality of life, mental health, chronic disease risk factors).

The socio-demographic module is used in each wave, while the other modules are used according to a predetermined schedule decided by the scientific advisory board. Figure 1 shows the modules uses in each wave. The questionnaire used in each wave can be downloaded from the HDSS web page https://hdss.fk.ugm.ac.id/en/codebook-data-en/.

Figure 2. The list of questionnaire modules used in Sleman HDSS

*waist-hip circumference

The implementation of main wave data collection is presented in Table 2

Table 2. Sleman HDSS core module data collection

Wave Year First data collection Last data collection
1 2015 15 January 2015 28 April 2015
2 2016 01 February 2016 17 June 2016
3 2017 13 March 2017 22 May 2017
4 2018 26 February 2018 16 May 2018
5 2019 04 March 2019 29 May 2019
6 2020 02 September 2020 31 October 2020
7 2021 22 September 2021 31 January 2022
8 2022 5 September 2022 29 December 2022