Quality of life (QoL) is a distinctive human aim only recently introduced as an important outcome and quality indicator for the management of patients with heart failure (HF).1,2 The World Health Organization defines QoL as “an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns.”3 This view reinforces the contemporary concept of QoL having a broad and multilayered scope, which should be considered when assessing it in the context of underlying diseases, such as chronic HF.4

HF is the leading cause of hospitalization in people over 65 years of age in developed countries.5 In Portugal, it affects approximately 770000 patients, with a prevalence of 16.54% in people aged ≥50 years.6,7

Traditionally, the primary endpoints of HF trials consisted of all-cause or cardiovascular mortality and/or HF hospitalizations. QoL and patient-reported health outcomes (PROs) have been viewed as “soft” endpoints, although they provide insight into treatment effects from the patient's perspective.8 In 2013, a clinical outcome endpoints consensus document in HF trials was published by the European Society of Cardiology (ESC), reporting symptoms and PROs as independent endpoints for HF trials. The document stated the need for development of validated and simpler instruments sensitive to changes in health status over time.1

There are several validated instruments to assess QoL in patients with HF. The two most used questionnaires are the Minnesota Living with Heart Failure Questionnaire (MLHFQ)9 and the Kansas City Cardiomyopathy Questionnaire (KCCQ).10 The use of these instruments, however, remains largely limited to clinical trials.11 They are both time-intensive, and their current use in real-world care is very limited.2,12 Other authors identified the MLHFQ as the most appropriate instrument for QoL assessment in HF patients, because it has a simple structure and is easy to administer.13

Multidisciplinary HF clinics reduce mortality and hospitalizations and are a class I recommendation in European and American HF guidelines. QoL improvement is a major goal of HF clinics and treatment algorithms for all HF patients.14–16 PROs represent excellent tools to promote patient-centered care and a real opportunity to integrate patients’ voices in healthcare quality assessment.12

The aim of this study was to validate a translated version of the original MLHFQ in a sample of Portuguese HF patients managed in a multidisciplinary HF clinic. In addition, this study aimed to identify associations of MLHFQ scores with other PROs measures.

This study aimed to validate the MLHFQ and to identify associations of MLHFQ scores with other clinical evaluations and PROs measures. Here we present the validation of the MLHFQ to European Portuguese and report the existence of three subscores: physical, emotional and social. All the scores were strongly associated with the NYHA functional class, and the MLHFQ total score was associated with all the studied variables. Additionally, to the best of our knowledge, this is the first study reporting associations between: (1) the physical score and both the Borg fatigue score and the 6MWD and (2) the emotional score and anxiety and depression HADS scores.

Recently, a working group of the ESC defined quality indicators for the care and outcomes of adults with HF, including a domain for the assessment of patients’ QoL and the recommendation of the use of a “validated tool”. The experts considered that QoL assessment by itself constitutes an accomplishment of that quality indicator, without setting any target score, given concerns about the feasibility of capturing QoL in clinical practice.2 The position of the ESC highlights the unmet need for a very pragmatic instrument in the assessment of HF-specific QoL. The MLHFQ is easy to administer, has a simple structure with 21 questions, answers displayed on a Likert scale, fits to one page only and takes approximately 5 minutes to complete.9 Gallagher et al. studied the acceptability and feasibility of implementing validated QoL instruments in HF clinics, reporting that the MLHFQ had a higher completion rate than the KCCQ, with all the questions answered by 85% vs 49% of patients, respectively.11

The validation sample in our study represented elderly patients of both sexes with many comorbidities, several HF etiologies, symptomatic HF, and similar proportion of reduced and preserved LVEF. This representation of HF patients from real world clinical practice is one of the strengths of this study. The analysis of the answers to the 21 questions of the MLHFQ revealed that there were only a few missing values. Noteworthy, 88.10% of the patients answered “No” to question 14 concerning HF hospitalization in the previous month. This may be because patients had optimized care and a low hospitalization rate.25

The Portuguese version of the MLHFQ validated in this study has a reliable total score and good internal consistency. The median total score (P25–P75) of the MLHFQ was 15 (6–33), indicating relatively good HF-related QoL, considering the range of possible total scores from 0 (zero) to 105. Gallagher et al reported an MLHFQ mean total score of 40.9±25.6 in 152 outpatients from two specialist cardiology outpatient clinics.11 It is well established that one-quarter to one-third of participants in HF trials show significant improvement in QoL when receiving placebo.27 This may reflect exposure to the beneficial environment trial, where patients are often followed more closely than in routine clinical care and healthcare providers pay particular attention to patient-reported symptoms.28 Likely, the same happens with patients under optimized care in the setting of multidisciplinary HF clinics, justifying the relatively low total score reported in this study. In fact, all the patients received education and optimized care through a HF management program, which was delivered by a multidisciplinary team of trained professionals.

This study reports the existence of three MLHFQ subscores: physical, emotional and social. This is in accordance with reports from several other authors that identified a social score.29 Bilbao et al. compared several authors’ proposals for social factors29 and recommended the use of Munyombwe et al. social factor30 because it has the best psychometric properties. When comparing the questions that compose the social score in our study and those proposed by Munyombwe et al., there is a match in questions 8, 9, 10 and 16. However, our study included question 11 but not questions 14 and 15.

Our validated version of the MLHFQ includes 20 of the 21 questions in one of the three subscores. Thus, considering subscores for the three-domain structure could be an alternative to the total score of the MLHFQ.29

The impact of HF has traditionally been measured using clinical tools, such as the NYHA classification or the 6MWT.31 The limitations of the NYHA classification include its subjective assessment and high interobserver variability, previously reported at 54%.32 In this study, the total and subdomains scores of the MLHFQ were strongly associated with the NYHA functional class. Other authors reported a significant association of HF-specific QoL scores with the NYHA functional class,11,33 highlighting the need for routine measurement of QoL in HF clinics. While QoL scores report the patient perspective, the NYHA functional class is typically rated from the clinician's perspective. Additionally, recent clinical trials have shown that the beneficial effects of HF medications in terms of symptoms, mortality and hospitalization, may not be related to improvements in QoL.28

This study revealed that the MLHFQ total score was associated with all the studied variables, namely: (1) 6MWD, (2) Borg fatigue score at the end of the 6MWT, (3) HADS depression and (4) HADS anxiety scores. These findings support the validity and reliability of the Portuguese version. The physical score was associated with fatigue and the 6MWD, the latter being an objective measure of exercise tolerance. The emotional score was significantly associated with both anxiety and depression HADS scores. However, the negative impact of anxiety and depression symptoms on the QoL of HF patients is well established in the literature.34,35

Notably, this study validated the MLHFQ in a sample with a balanced representation of HF patients with reduced and preserved LVEF. Currently, HF guidelines report interventions aimed at improving QoL only in patients with reduced LVEF.14 However, Chandra et al. reported that HF patients with preserved LVEF generally have more impaired QoL than patients with reduced LVEF. Additionally, they reported regional differences in QoL among patients with preserved LVEF.33 Thus, this study's version of the MLHFQ has potential high value, opening a door to research in the field of QoL in patients with preserved LVEF followed in Portuguese HF clinics. Nowadays, it is estimated that 650000 people live in Portugal with HF and preserved LVEF.7

Our study has some limitations that we must acknowledge. This was a single-center study conducted at an HF clinic and was not designed to include a nationally representative sample. The responsiveness of this version of the MLHFQ was not tested, although we plan to do so in the future. Nevertheless, our findings are a step forward to a better QoL assessment of Portuguese HF patients.

This study supports the validity and reliability of the Portuguese MLHFQ version, recognizing the existence of a total score and three subscores: physical, emotional and social scores. All the scores were associated with the NYHA functional class. In addition, we report new and convincing evidence that the physical score is associated with the 6MWD and Borg fatigue score at the end of the 6MWT, and that the emotional score is associated with HADS anxiety and depression scores.

We believe that this MLHFQ validated version can help to overcome the challenge of QoL assessment in everyday clinical practice in Portuguese HF clinics using a pragmatic approach. Further research is needed to assess the responsiveness of the scale and the impact of routine QoL assessment in clinical practice.

IM and SV designed the study. IM, SV and AGM collected the data. IM, AGP and MS analyzed and interpreted the data. IM and MS performed the statistical analysis and prepared the manuscript. All authors vouch for the accuracy and completeness of the data and analysis. All the authors contributed to the article and read and approved the final manuscript.

Health Ethics Commission (CES) of the Porto Hospital Center. Reference number 2017.040 (040-DEFI/040-CES).

This research received no funding.

The authors have no conflicts of interest to declare.