Thirst and its Predictors in Patients with Heart Failure

Abstract

Background: Thirst is a subjective sensation of throat and mouth dryness that leads to a powerful craving to drink. In healthy people, thirst is important to maintain fluid volume balance, therefore maintaining homeostasis. This sensation can be strong enough to cause uncontrollable water intake. Thirst is one of the most unpleasant symptoms facing patients with HF. Many factors are associated with thirst such as the prolonged neurohormonal activation, medications, fluid restrictions, and emotions such as anxiety and depression. One fifth of patients with HF experience thirst and this experience might persist for 18 months or more after discharge. HF patients were found to score higher on the Thirst Intensity Scale than patients without HF. Despite its prevalence, thirst has been rarely studied. There are no studies that address the relationship between thirst and salt intake among patients with HF.

Aim: The main aims of the study are to describe the prevalence and characteristics of thirst among patients with HF; examine the association between thirst and behaviors related to salt intake; and identify predictors of thirst using relevant demographic and clinical variables.

Methods: a descriptive correlational study design was used. The study was conducted in the coronary care unit at American University of Beirut Medical Center (AUBMC) and Rafik Hariri University Hospital (RHUH), in addition to the HF outpatient clinic at AUBMC. The targeted population included HF patients with HF-rEF, HE-pEF and midrange EF-HF, and with NYHA class I-III. Data were collected between December 2021 and April 2022. Institutional review board at AUB and RHUH, in addition to the administration approval in both hospitals were secured. A recruiter (cardiology nurse) was assigned to enroll eligible patients from AUBMC CCU, HF outpatient clinic and RHUH CCU. Patients who approved to participate were directed by the recruiter with their mobile number to the researcher. The researcher called them for the interview and sent the informed consent through WhatsApp. The average interview time was around 25 minutes. The interview included questionnaires related to thirst, as well as knowledge, behaviors, and attitudes related to salt consumption in addition to the patient health questionnaire (PHQ2).

Data Analysis: Statistical analysis included descriptive statistics (means and standard deviations, and frequencies and percentages, depending on the level of measurement). Bivariate analyses included Pearson R correlation coefficient, Spearman Rho correlation coefficient, t-tests, Chi-squared test and ANOVA to examine associations between variables. Multiple linear regression analysis was used to examine the predictors of thirst.

Results: a sample of 90 patients were interviewed (76.92 % response rate). 50% were recruited from CCU and the other half from the clinic. The majority were males (57.8%), married (74.4%), living with partners (70%) and had university education (41.1%). The mean age was 65.83±12.94 years. Most participants were NYHA class II (48.9%) with mean EF 37.55±11.45%. The most frequent comorbidities were diabetes mellitus II (63.3%) and hypertension (67.8%). The average thirst intensity was 3.82±2.21. The prevalence of thirst was 23 % with most participants reporting thirst a couple of times per week (43.3%) and per month (26.7%). Morning was the most reported time of thirst (41.1%). The mean thirst distress score was 23.58+7.66, with most participants being in the moderate (31.1%) and strong (33.3%) thirst distress groups. The mean knowledge score was 14.2±4.6, with only few participants identifying processed food as the main source of salt (34.4%), the relationship between salt and sodium (25.6%) and the recommended salt amount per day (20%). The mean attitude score was 3.41±1.34. The two main motivators to reduce salt were change in health condition (43.3%) and doctor's advice (43.3%). Good taste of salt was the most reported barrier against reducing its consumption (63.3%). Majority of the sample (83.3%) are cutting down on salt, and get their health information from their doctor (64.4%). Most participants never add salt on the table (63.3%) and while cooking (40%). The mean PHQ-2 score was 0.77±1.03. Being prescribed salt restriction was associated with thirst intensity and distress (p-value 0.003 and 0.035, respectively). No clear result regarding the association of fluid restriction with thirst. Ejection fraction, antidepressants and the PHQ2 score were the predictors of thirst distress in the regression model. Whereas, age, ejection fraction, diastolic blood pressures, antidepressants, statins and PHQ-2 score were the predictors of thirst intensity in the regression model.

Conclusion: thirst is prevalent in the sample despite the need for future studies. This study was guided using the theory of unpleasant symptoms. Many factors were associated with thirst, including physiological, psychological, and situational. It was significant that thirst intensity is more associated with younger age and female gender. Depression was highly associated with higher thirst. There is a need for thirst assessment in healthcare facilities as well as proper patients’ education. Future studies are essential in our region to understand thirst more thoroughly.