Diagnosed Hypertension at the Baseline in Predicting the Trajectory of Depressive Symptoms Among Older Mexican Americans: A Longitudinal Study

Background and Purpose:Depressive symptoms in hypertensive individuals are correlated with poorer health outcomes, including increased medical expenses, decreased quality of life, reduced compliance with treatment, and increased mortality rate. Understanding the trajectory of depressive symptoms among hypertensive individuals is an important step to promote related health outcomes produced by the comorbidity of depression and hypertension. Prospective studies have shown that depressive symptoms are associated with an elevated risk of the development of hypertension, while the discussion about the development of depressive symptoms in hypertensive individuals has received little attention.The purpose of the study is to examine the relationship between diagnosed hypertension at the baseline and the trajectory of depressive symptoms among older Mexican Americans.

Methods: Data was from wave 1 to wave 8 of the Hispanic Established Population for the Epidemiological Study of the Elderly Series collected from 1993 to 2013. At the baseline, data were collected from a representative sample of 3050 community-dwelling Mexican Americans aged 65 years and older who reside in Arizona, California, Colorado, New Mexico, and Texas. Only respondents from the baseline cohort in each wave were included for analysis. Descriptive statistics were generated to describe sample characteristics at the baseline. Longitudinal hierarchical linear regression was conducted to investigate the relationship between diagnosed hypertension at the baseline and the trajectory of depressive symptoms across eight waves. 

Measures:Diagnosed hypertension at the baseline was defined by self-reported doctor diagnosis. Depressive symptoms were measured by the CESD-20. Physical function was indicated by ADL and IADL (time-varying covariates). Chronic stressors at the baseline were quantified by the number of traumatic events experienced by respondents in the past year. Living arrangement was categorized by living with children, spouse, other family members, living alone, and living in the institution. Other sociodemographic variables included sex, education level, and marital status.

Results:Baseline participants have a mean age of 73.6 (6.8) years and a mean education of 4.8 (3.9) years. The original cohort consisted of 42.3% male, 57.7% female, 55.5% married individuals, approximately 46% individuals living with spouse, and 42% individuals with diagnosed hypertension. The estimated trajectory of depressive symptoms was modeled from 11,275 assessments (mean[SD] per participant, 9.1[0.12]; range,0-57). Results from regression analyses showed that having diagnosed hypertension at the baseline predicted a significant increase in depressive symptoms by 0.48. Chronic stressors, female sex, difficulties in IADL and ADL were strong predictors for increased depressive symptoms, of which the effect of ADL on depressive symptoms has grown to be greater over time. Living with children and higher education level significantly decreased depressive symptoms.

Conclusions and Implications: Using repeated assessments of depressive symptoms for eight waves, the study revealed that diagnosed hypertension is a strong predictor for increased depressive symptoms longitudinally among older Mexican Americans. The present findings are important because the study provides a longitudinal pattern in the association of depressive symptoms and preexistent hypertensive condition. This pattern could be explained by increased psychological distress induced by hypertension awareness and risk factors related to hypertension that may affect depressive symptoms.