Systematic hypertension screening and follow-up attrition in Thai prisons: A cross-sectional study

The living conditions in prisons may contribute to the development of hypertension. The effectiveness of hypertension screening depends on both the willingness of individuals to participate and the presence of security policies that support completion of screening. This study examined the prevalence of hypertension in prisons by using a systematic screening approach, identified associated risk factors, and examined the rate of loss to follow-up after hypertension screening.

This cross-sectional study was conducted in five prisons in Thailand and identified 11,290 individuals aged 18 years or older who met the inclusion criteria. Trained peer volunteers administered structured questionnaires and measured the participants' blood pressure, height, and weight. Individuals who were screened as positive (score ⩾ 1) were further evaluated by nurses. Those with blood pressure readings of 140/90 mm Hg or higher were referred to hospitals for diagnostic confirmation and treatment. Logistic regression was used to analyze associated factors.

Of the 11,290 eligible individuals who were identified, 98.6% agreed to undergo hypertension screening. The overall prevalence of physician-confirmed hypertension was 4.0%. The prevalence was 5.8% among individuals aged 35 years or older, 6.4% among those with a family history of hypertension, and 3.5% among individuals incarcerated for 2 years or longer. Age 35 years or older (adjusted odds ratio (OR) = 3.21; 95% confidence interval (CI): 2.52-4.08) and a family history of hypertension (adjusted OR = 1.81; 95% CI: 1.46-2.23) were significantly associated with hypertension, whereas incarceration for 2 years or longer was protective (adjusted OR = 0.72; 95% CI: 0.59-0.88). The overall loss to follow-up rate was 6.7%.

The prevalence of hypertension among incarcerated individuals in Thailand was low, suggesting that prison living conditions may not be as detrimental to health as commonly perceived. However, the observed loss to follow-up highlights the importance of strategies to improve engagement and ensure timely access to diagnostic and treatment services throughout the screening and diagnostic process.