Socioeconomic impacts on adherence are understudied, particularly in disadvantaged areas. This study aimed to evaluate socioeconomic factors on medication adherence among patients with hypertension in Lombok, Indonesia. A cross-sectional survey was conducted in all six public hospital outpatient clinics in Lombok in 2017. Data was obtained using a validated questionnaire to which the Morisky Green Levine Adherence Scale (MGLS) questionnaire was used to assess medication adherence. Binary logistic regression was performed to determine independent socioeconomic associations. A total of 693 patients with hypertension were included (response rate 84%). The majority had low adherence (76.2%). Significant independent associations were reported between setting and education with adherence (rural versus urban setting: odds ratio 3.54, p<0.001; primary versus university level education: odds ratio 5.39, p<0.001). Socioeconomic associations provide some basis for the development of patient and population-based interventions to improve adherence among patients with hypertension in Indonesia, particularly in disadvantaged areas.

socioeconomic, medication adherence, hypertension, Indonesia, developing country

Indonesia is the largest archipelagic country and one of the most populous in the world, with more than 250 million people (MoH-RI 2014). In recent decades, the burden of cardiovascular diseases (CVD) in Indonesia have increased significantly, with stroke and coronary heart diseases being ranked the first and second leading causes of death in 2014 (21.1% and 12.9%, respectively) (MoH-RI 2014). Hypertension, defined as elevated blood pressure (BP, mm Hg) ≥140 systolic and/or ≥90 diastolic, has been identified as the leading risk factor in terms of its contribution to the burden of CVD (MoH-RI 2014). Based on the data from Basic Health Research, the prevalence of hypertension among adults aged ≥18 years in Indonesia had risen from 25.8% or 42.1 million in 2013 to 34.1% of the population in 2018 (MoH-RI 2013; MoH-RI 2019a). This has resulted in increased cost of hypertension related services each year, with expenditures of 2.8 trillion Indonesian Rupiah (IDR) in 2017 to 3 trillion IDR in 2018 (MoH-RI 2019a). Hence, the Indonesian Government has included hypertension management as one of the national health indicators (RoI 2015).

Strategies to control hypertension include prescribing antihypertensive medications in conjunction with behavioural and lifestyle modifications (Whelton et al. 2017). It was reported, however, of those treated in high income countries with medications, approximately 50% maintained good adherence one year after initiation and achieved well controlled BP. This level was even lower in low-middle income countries (Hill et al. 2011; Burnier and Egan 2019). While many factors might contribute to the lack of adherence; lower socioeconomic conditions have been frequently considered as barriers for adherence to treatment in some previous studies (Basu and Millet 2013; Sandoval et al. 2018; de Terline et al. 2019). Socioeconomic status can be seen as a multidimensional construct referring to an individual’s position relative to other people in the community; it is commonly measured by level of income, educational attainment, and occupational group (Stringhini et al. 2018).

Indonesia is a developing country and is classified as a low-to-middle income country (MoH-RI 2019b). With a wide geographical area, varied socioeconomic status across the country may impact on adherence rates in specific regions.West Nusa Tenggara is a province located in the eastern part of Indonesia, which is considered to be disadvantaged compared to its western counterparts; based on the 2018 survey, the Human Development Index (HDI) – to measure quality of life based on three dimensions (i.e. health, literacy, and standard of living) – in this province was 67.3 which was lower than the national figure of 71.9 (MoH-RI 2019b). This is further complicated with limited health resources in this province which is possibly affecting access. The ratio of primary health centres (Puskesmas) is 1.43 per 30,000 population; while the ratio of hospital beds per 1000 population was 0.71, which are the lowest across Indonesia (BPS NTB 2017).

It was reported that West Nusa Tenggara ranked 15 out of 33 provinces in Indonesia with the highest prevalence of hypertension being 24.3% in the year 2013, and has tended to increase each year (MoH-RI 2013). Previous small studies in Indonesia have mainly reported the levels of adherence among patients with hypertension which is variable across Indonesia, ranging from 20%–59% (Chusna et al. 2014; Liberty et al. 2017; Sinuraya et al. 2018; Rahmadani and Sari 2018); however, the impact of socioeconomic status variations on adherence are understudied. The knowledge of any such association would be of importance, particularly in the disadvantaged areas with limited health resources such as West Nusa Tenggara, in helping practitioners to prioritise patients who are less likely to adhere to their treatment. Such data would also provide a basis for the development of patient-based and population-based hypertension services to address the regional needs to improve public health. This initial study aimed to evaluate socioeconomic impacts on adherence to medications among patients with hypertension in hospital outpatient settings in Lombok Island, West Nusa Tenggara Province, Indonesia.

The data collection instrument and methodology used in this study were approved by the Ethics Committee of University of Surabaya, Indonesia (No. 007/KE/XII/2017), and the research study granted official permission from each hospital.

Of 822 patients with hypertension approached, 693 patients with hypertension in six hospital outpatient settings in Lombok consented: hospital A (n=237/262), hospital B (n=104/127), hospital C (n=107/131), hospital D (n=90/115), hospital E (n=107/126) and hospital F (n=48/61), giving a total response rate of 84%. Hospitals A and B were located in Mataram City (urban setting), while the other four were located outside of the city (rural setting). More female patients with hypertension volunteered than males, in all settings. The majority of participants were in the age group of >50 years (74.5%),and were diagnosed with hypertension between 1 to 5 years or more than 10 years (48.5% versus 26.6%, respectively). More than 60% of the patients were being treated with combination antihypertensive agents, and the majority reported two or more associated comorbidities. The characteristics of participants in each setting and in total are summarised in Table 1.

Table 1 also presented patients’ socioeconomic data. Approximately 50% of the partipants had a basic level of primary education, either completed or not. About half of the participants were unemployed or were seniors, and had a low income of less than 1 million IDR per month (or approximately USD $71). Of those who were employed, they mainly worked as civil servants or farm workers (13.3% versus 18.2%, respectively).

The score responses to the questions of the MGLS are presented in Table 1. In general, patients had low adherence to their hypertensive medications (76.2%). Hospital D (rural setting) had the highest number of patients wih low adherence (90%), while hospital A (urban setting) had the highest number of patients with high adherence (19.0% respectively).

Univariate analysis of individual socioeconomic factors – i.e. education, employment, income or setting – and levels of adherence showed statistically significant associations (all p-values <0.001). However, the binary logistic regression indicated only setting and education were independently associated with medication adherence. Patients in urban settings were 3.54 times more likely to have adequate adherence compared to those in rural settings (95% CI 2.30–5.45, Wald χ²(1) = 33.03, p <0.001); while the odds of those with university-education level had adequate adherence was 5.39 times compared to those with primary-education level (95% CI 2.52 to 11.51, Wald χ²(1) = 18.93, p < 0.001). Detailed results of the univariate analyses and the logistic regression can be seen in Tables 2, 3.

This study has provided insight to the profiles of patients with hypertension in Lombok, West Nusa Tenggara, Indonesia. A majority of patients reported low adherence, and this was associated with socioeconomic status, particularly setting (rural versus urban) and education. This study included large convenience prospective sample that consisted of more females with hypertension; although not a random sample, this finding was comparable to the Indonesia Family Life Survey (IFLS) in 2016 where hypertension was significantly more prevalent in women than men (52.3% versus 43.1%) (Hussain et al. 2016). This survey also reported that regardless of gender, the prevalence of hypertension increased significantly with age (p-value for trend <0.001) (Hussain et al. 2016). This is in line with findings in this study where almost half of patients with hypertension were elderly. With regards to the patients’ socioeconomic status, it was found that the majority had a low level of education, with a low level of income. This might reflect the Human Development Index (HDI) in West Nusa Tenggara which was reported to be lower than the national figure (67.3 versus 71.93, respectively) (MoH-RI 2019b).

The four items MGLS used to measure medication adherence among patients with hypertension in this study showed less than 25% of patients had moderate to high adherence. International studies have reported that adherence with antihypertensive medications is typically 50% and in developing countries is lower (Hill et al. 2011; Burnier and Egan 2019). Findings in Indonesia have shown different adherence levels among patients with hypertension across various areas, ranging from 20%–59% (Chusna et al. 2014; Liberty et al. 2017; Rahmadani and Sari 2018; Sinuraya et al. 2018). As the largest archipelagic country, Indonesia has a highly diverse environmental and socioeconomic status; while it has been suggested that that patients’ socioeconomic status is frequently associated with medication adherence (Basu and Millet 2013; Sandoval et al. 2018; de Terteline et al. 2019).

Among sociodemographic factors, the logistic regression indicated that rural-urban setting and education were independently associated with medication adherence among patients with hypertension in Lombok. Patients in urban settings showed significantly higher adherence levels compared to those in rural areas. Many factors could influence increasing rates of non-adherence among those living in rural areas, such as increasing rates of poverty and lower income, reduced rates of insurance coverage, and increased distance to health care services among individuals living in rural communities (Anderson et al. 2015; Haveman et al. 2015).

In addition to rural-urban setting, education also had a positive association with adherence (p < 0.001). In parallel with this, studies in Bandung, which is located in the western part of Indonesia, have reported that more patients with higher education have better adherence levels (Sinuraya et al. 2018). Similar results have been reported in other developing countries, such as Nigeria and Ghana (Boima et al. 2015). It has been suggested that higher educational levels might relate to better health literacy (Mezuk et al. 2011; Olesen et al. 2011), thus improving adherence. Several studies have suggested that it is knowledge specific to hypertension that has a significant association with patient adherence to antihypertensive therapy (Ghembaza et al. 2014; Algabbani 2020). Hence, strategies to improve adherence in Lombok should consider to initially target those living in rural areas with lower education levels. It must be noted patients in these samples have accessed health care and there maybe further unmet requirements.

With regards to occupation, although the univariate analysis reported significant associations with adherence, these were not independently associated in the logistic regression. Rather than the occupation itself, the educational levels might better explain differences in the adherence levels and has been reported as a significant predictor in this study. In addition to occupation, income was not significantly associated with medication adherence among patients with hypertension. The implementation of the National Health Insurance (Jaminan Kesehatan Nasional, JKN) starting in 2014 has enabled most Indonesians to have adequate access to more affordable and higher quality healthcare (Agustina et al. 2019). Hence, regardless of income, patients with hypertension in this study should be able to obtain medications they need; and thus non-adherence due to lack of medicine access should not be an issue.

This study has some limitations. This study specifically evaluated the profiles of patients with hypertension in Lombok which has a lower socioeconomic status; thus, some caution should be exercised in generalising these results. Although not a random sample, this study was a large convenience sample with a response rate of 84%. The characteristics of respondents in this sudy were comparable to the Lombok population with regard to the educational level; based on the data in 2018, 51.1% of the population had none or primary-level education (BPS NTB 2019). It should be noted that some self-reported data could be biased when patients could not accurately recall the information asked (recall bias). However, the questionnaire in this study was designed to include information regarding patients’ behaviour in taking medication for a short period of time, i.e. in the last month, hence issues with recall bias might be minimal. Further research to explore external factors would be worthwhile to provide more comprehensive data to understand patient non-adherence in this disadvantaged area in Indonesia.

This initial study has shown poor medication adherence among patients with hypertension in Lombok, providing some insight into the health profile in a more disadvantaged area in Indonesia. The development of future interventions to improve adherence should consider patients’ socioeconomics in this context, in particular those living in rural settings and having lower educational levels. These findings have important health and patient management issues as prescribers may not currently be aware of this low level of adherence.

No specific funds, grants or other support was received.

The authors declare that there is no conflicts of interest.