- Open Access
Portuguese validation of the Cambridge pulmonary hypertension outcome review (CAMPHOR) questionnaire
Health and Quality of Life Outcomes volume 14, Article number: 110 (2016)
Patients with pulmonary arterial hypertension (PAH) and other forms of precapillary pulmonary hypertension (PH) have impaired quality of life (QoL). The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) is a PH-specific patient-reported outcome measure that assesses symptoms, activity limitations and QoL. It was originally developed in UK-English. The main objective of this study was to create an adaptation of the CAMPHOR suitable for a Portuguese-speaking population.
A multi-step approach was followed: bilingual and lay panel translation; cognitive debriefing interviews; and psychometric testing in repeated postal surveys (2 weeks apart) including assessment of internal consistency, reproducibility and validity. The Nottingham Health Profile (NHP) questionnaire was used as a comparator instrument to test convergent validity.
The CAMPHOR was translated without difficulty by the two panels. Cognitive debriefing interviews showed the questionnaire was easily understood and considered relevant to patients’ experience with their illness. Psychometric evaluation was performed with 50 PAH patients (47 ± 14 years, 37 women). Cronbach’s alpha coefficients showed good internal consistency for the three CAMPHOR scales [Symptoms = 0.95; Activities = 0.93 and QoL = 0.94]. Test-retest coefficients showed that all scales had excellent reliability (Symptoms = 0.94; Activities = 0.89 and QoL = 0.93), indicating low levels of random measurement error. The CAMPHOR correlated as expected with the NHP. The magnitude of correlations followed a similar pattern to those in the original development study. The CAMPHOR also exhibited evidence of known group validity in its ability to distinguish between self-reported severity and general health groups.
A valid and reliable version of the CAMPHOR questionnaire for the European Portuguese-speaking population was developed and is recommended for use.
Precapillary pulmonary hypertension (PH) is characterized by an obstructive vasculopathy of the pulmonary circulation leading to increased pulmonary arterial pressure, pulmonary vascular resistance and, eventually, right-sided heart failure and death [1–4]. Multiple conditions and comorbidities are associated with PH . Patients present unspecific symptoms, such as exertion dyspnoea, fatigue, chest pain, palpitations, oedema or syncope, resulting in frequently delayed diagnosis .
PH prognosis improved in recent years due to better understanding of PH pathobiology, availability of new drugs (endothelin receptor antagonists, phosphodiesterase-5 inhibitors, soluble guanylate cyclase stimulators and prostacyclin analogues) and renewed therapeutic strategies [6–9]. Still, a cure for pulmonary arterial hypertension (PAH) and other precapillary forms of PH is far from being available.
The impact of the disease and some types of treatment, like parenteral drugs or oxygen administration, can lead to impaired QoL, social isolation, as well as anxiety and depression . Assessments of health-related quality of life (HRQoL) are currently recommended during global evaluation of PH patients, both in the context of clinical trials and routine clinical practice. Although some generic questionnaires such as the Short Form 36 Health Survey (SF-36) have shown prognostic value in PAH [11, 12], generally the use of generic questionnaires or those specific to other conditions has important limitations if they are not eventually validated in an appropriate PH sample . Several attempts to evaluate other generic questionnaires, such as Nottingham Health Profile (NHP), and EuroQol Group 5-Dimension Self-Report Questionnaire (EQ-5D) or other disease-specific questionnaires, such as the Minnesota Living with Heart Failure Questionnaire (MLHFQ) or the Chronic Heart Failure questionnaire (CHQ), have failed to prove their specificity for the disease both in real life settings and clinical trials [14–21]. This lead to the development of disease-specific questionnaires such as the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) [12, 13], and more recently, the emPHasis-10  and the Pulmonary Arterial Hypertension-Symptoms and Impact (PAH-SYMPACT) , which are under evaluation. Disease-specific assessment instruments provide outcome measures that are more relevant to actual patient experience. Evidence also demonstrates that these outcomes are more sensitive to change than generic ones [24–29].
The CAMPHOR was originally developed and validated in the United Kingdom,  and subsequently adapted for use in the US, Canada, Australia/New Zealand, Sweden and Austria/Germany/Switzerland [13, 31–34]. It consists of three different scales: a 25-item Symptom scale, to assess energy, breathlessness and mood (low score indicates minimal symptoms); a 15-item Activity limitations scale with a 3-point rating system (score ranges from 0 to 30, lower score indicates minimal activity limitation); and a 25-item QoL scale (lower score indicates better QoL) .
This paper describes the Portuguese translation and validation of the CAMPHOR. The development of this language version will allow the use of CAMPHOR in routine clinical practice and in clinical trials in the European Portuguese-speaking population with PAH and other precapillary forms of PH.
CAMPHOR translation and validation was based in three main stages: (1) bilingual and lay panel translation; (2) cognitive debriefing interviews; and (3) psychometric testing in repeated postal surveys, 2 weeks apart. Psychometric analyses included test-retest reliability, internal consistency, convergent validity, and known group validity. The study was approved by the Independent Ethics Committee of Centro Hospitalar do Porto and written informed consent was obtained from all participants before enrolment in the study.
Step 1: Translation
The bilingual panel involved a group of six participants who had Portuguese as their primary language and were fluent in Portuguese and English. Participants were excluded if they had medical training, were a professional translator or if they were familiar with PH. The Principal Investigator lead the panel discussion and a representative of the original measure development team attended the meeting, advising in situations of difficult decision-making by explaining the original concept of the items. Each scale item was discussed until agreement was reached.
The main goal of this panel was to provide the initial translation of the questionnaire. When translating the content, emphasis was placed on achieving conceptual equivalence rather than providing a literal translation. In situations where agreement could not be reached, the panel provided alternative translations for later consideration by the lay panel.
A separate lay translation panel consisted of a group of five monolingual Portuguese-speaking participants with an average education level. The Portuguese translation of the questionnaire developed by the bilingual panel was presented and discussed. Participants were asked to comment on the language in terms of comprehension and acceptability. The main goal of this panel was to ensure that the language used in the questionnaire was adequate for respondents with average educational level.
Step 2: Cognitive Debriefing Interviews
Face-to-face cognitive debriefing interviews were conducted with 10 patients in the PH outpatient clinic at Centro Hospitalar do Porto—Hospital Santo António (Table 1). The purpose of the interviews was to assess the relevance, acceptability, comprehensiveness and understandability of the questionnaire items.
During the interviews, participants were asked to complete the questionnaire, comment on any aspect they thought had been omitted and answer some specific questions about the questionnaire.
Step 3: Validation
To validate the Portuguese version of the CAMPHOR, 50 patients with precapillary PH were recruited in the outpatient clinic at Centro Hospitalar do Porto—Hospital Santo António, between 14SEP2012 and 16SEP2013. Their mean disease duration was 57.06 (SD = 58.81) months. During a programmed visit, participants were informed about the study methodology, signed an informed consent form and received packs containing written instructions, two samples of the CAMPHOR and NHP questionnaires (to be filled in at home, 2 weeks apart) and a pre-paid postal return envelope. All participants received unique identification numbers. Only returned completed surveys were considered for analysis.
Demographic (birth date, gender, marital and working status) and clinical data (PH aetiology, WHO/NYHA functional class, 6MWD, NT-proBNP, treatment) were gathered from the PH clinic dedicated informatics system (PAHTool®, Inovultus Lda, Portugal) and exported to Microsoft Excel.
The distributional properties of the measures were explored through descriptive statistics [mean, standard deviation, median and interquartile range (IQR) and floor and ceiling effects (% of patients scoring the minimum and maximum scores)]. Scores were compared by age and gender.
Internal consistency was assessed using Cronbach’s alpha coefficients. Alpha measures the extent to which the items in a scale are inter-related. A low alpha (below 0.7) indicates that the items do not work together to form a scale . In addition, item total correlations (ITCs) should be between 0.2 and 0.8.
The test-retest reliability of a measure is an estimate of its reproducibility over time when no change in the condition has taken place. It is calculated by correlating scores obtained on two different occasions. Spearman’s rank correlation coefficient was used for the analyses. For low random measurement error, a correlation coefficient of ≥0.85 is necessary (26).
Convergent validity is used to determine the level of association between scores on one scale and those on a comparator scale that measures the same or related constructs. For the present investigation, the NHP was used as a comparator instrument. Portuguese CAMPHOR scores were correlated with NHP scores by Spearman rank correlation coefficients.
Known group validity can be assessed by testing the ability of a measure to distinguish between groups of people that differ according to some known factor. The factors used for the present investigation were self-reported general health (poor, fair, good, very good) and severity of symptoms (mild, moderate and severe).
Non-parametric tests for independent samples (Mann-Whitney U Test for two groups or Kruskal-Wallis One-Way Analysis of Variance for three or more groups) were employed to test for differences in CAMPHOR scores between groups.
Statistical analyses were performed using IBM SPSS version 21.0.
Equal numbers of men and women (3 males and 3 females) were included in the bilingual panel. The mean age of the participants was 37 years (range 21–52 years). Most of the translation process occurred with little discussion and disagreement between panel participants. The main challenge during the translation was the selection of words that would allow the items to be expressed colloquially.
The lay panel involved one male and four female participants with a mean age of 37 years (range 16–66 years). The panel reported that the language of the questionnaire was generally good, objective, direct, and clear. However, panel members suggested some alternative wording to improve understanding. For example, item 1 of the Symptoms scale was changed because the Lay Panel thought that “without strengths” rather than “low strengths” would be easier to understand.
Cognitive debriefing interviews
All CAMPHOR questionnaires were completed within a mean of 17 min (standard deviation 10.5 min). In general, patients understood the questionnaire and assessed it as being simple and easy to complete. Three elderly, rural, low literacy patients needed supplementary information to fully understand the instructions. All patients found that the questionnaire reflected their health condition and daily activities. The questionnaire’s content was considered appropriate, relevant and comprehensive. No questionnaire items were identified as inappropriate or unacceptable.
Fifty patients were recruited (Time 1) and 47 (94 %) completed and returned the questionnaires. Three subjects withdrew from the study, one was lost to follow up and two others were submitted to surgery between the surveys. The mean time between repeated post surveys was 14.2 days (median 14.0; n = 47). Main PH aetiologies are shown in Table 1.
Questionnaire descriptive scores
Descriptive statistics at Time 1 and Time 2 are shown in Table 3.
Floor (>10 % of patients scoring minimum) effects were identified in the CAMPHOR QoL scale Time 1 and the CAMPHOR QoL and Symptoms scales at Time 2. However, this is likely to reflect the mild nature of a subgroup of the sample. A possible ceiling effect might have occurred, since 16.3 % of the patients reached the maximum score in the QoL scale at Time 1. These effects were observed in the NHP scales.
Internal consistency and reproducibility
Cronbach’s alpha coefficients results are summarized in Table 4. The scales of Portuguese CAMPHOR showed excellent internal consistency with scales ranging between (0.93 and 0.95). Inter-item total correlations for each item are shown in Additional file 1: Tables S1, S2, S3. Reproducibility was above the required 0.85 level for all three CAMPHOR scales: Symptoms = 0.94, Activity limitations = 0.89 and QoL = 0.93.
Table 5 shows the correlation between CAMPHOR and NHP (six sections and NHP-D) scales at Time 1. High correlations were observed between CAMPHOR symptoms and Emotional reactions, Physical mobility and Energy showing the importance of these factors on PH symptomatology. As expected, CAMPHOR Activities correlated more strongly with Physical mobility. The QoL scale correlated more strongly with Energy, Emotional reactions, Physical mobility and Overall distress, indicating that multiple factors influence QoL in PH.
Association of CAMPHOR scores with demographic factors
No significant differences in CAMPHOR scores were found between participants grouped by age (above versus below median age) or gender.
Known group validity
Table 6 shows the results of the known groups analyses. Significant differences in ASQoL scores were observed between patients grouped by overall general health and perceived severity of disease.
Current guidelines recommend initial and follow-up disease severity and QoL assessments to support decisions regarding PH treatment . Previous validation of the CAMPHOR questionnaire in other geographical and cultural contexts demonstrated its superior specificity for PH versus general questionnaires, such as NHP, SF-36 or LHFQ. Furthermore, the development of the CAMPHOR utility index added the possibility of cost-utility analyses, which is particularly relevant for PH disease management .
Our study demonstrates that our European Portuguese version of CAMPHOR is a valid, internally consistent and reliable patient-reported outcome measure for the European Portuguese-speaking population with precapillary PH. This study was conducted exclusively in Portugal, therefore the use of our version in other Portuguese-speaking countries cannot be recommended, due to significant differences in culture, literacy and language (both in terms of semantics and vocabulary).
Most of the patients in the cognitive debriefing panels reported that the instrument was easy to complete and all patients reported that the questionnaire covered all important aspects of their experience with the disease. Three patients needed, nonetheless, additional information to fully understand the instructions during the cognitive debriefing interviews; these were older patients, from rural settings and with low literacy skills, and after additional clarifications, they finally were able to understand the instructions. In our study, patients took a mean of 17 min to complete the questionnaire, which is substantially longer than patients in the original instrument (10 min)  and more in line with data from the German translation (15 min) . We hypothesise that this longer completion time could be associated with lower literacy and higher proportions of patients from rural contexts in our population, however, literacy was not evaluated in our sample hampering further clarification.
In this study, the proportion of patients reaching maximum scores in the CAMPHOR QoL scale was surprisingly high, particularly when compared to previous validation studies (16.3 % vs. 0.0–0.7 % in other studies [13, 30–34]), which could be suggestive of a substantial ceiling effect. These results, could potentially be explained by disease severity, comorbidities, oxygen use, or even literacy. However, the proportion of patients reaching maximum scores is actually similar (or even higher) in the NHP comparator scale, which could be indicative of a tendency to the extremes in this population rather than a substantial ceiling effect. Given the similar results observed in the NHP comparator scale we do not envision this possible ceiling effect as a major limitation to the clinical use of this European Portuguese translation of CAMPHOR.
We found significant relationships between the CAMPHOR scales and the relevant domains of the NHP and the magnitude of the correlations followed a similar pattern to those described in the original development study . The CAMPHOR also showed evidence of known group validity in its ability to distinguish between groups of patients known to differ between self-ratings of disease severity and general health. The study showed that patients with precapillary PH experienced diminished QoL and increased symptoms and functional limitations. Results are consistent with the findings that patients with PH experience impairment in HRQoL [32, 33].
The major limitation of the present study is the small sample size, but given the low prevalence of precapillary PH related disease it can be considered an adequate sample for the purpose. Further studies to demonstrate CAMPHOR clinical validity, namely correlations with NYHA/WHO functional class, 6MWD and biomarkers, in the Portuguese population are being conducted.
In conclusion, this study gave sufficient evidence that our adaptation of CAMPHOR is an effective and consistent tool in European Portuguese-speaking population with precapillary PH. Incorporating this questionnaire in future clinical trials and especially in clinical practice will improve our global clinical evaluation of the PH patient and will improve knowledge of the health impact of PH. Routine HRQoL evaluation at first presentation and regularly during follow-up can help to educate/familiarize the patient with these tools and help physicians make evidence-based decisions.
6MWD, 6-min waling distance; CAMPHOR, Cambridge Pulmonary Hypertension Outcome Review; HRQoL, health-related quality of life; IQR, interquartile range; ITC, item total correlation; MLHFQ, Minnesota Living with Heart Failure Questionnaire; NHP, Nottingham Health Profile; NYHA/WHO, New York Heart Association/World Health Organisation; PAH, pulmonary arterial hypertension; PH, pulmonary hypertension; QoL, quality of life; SF-36, short form 36 health survey
Wagenvoort C, Wagenvoort N. Pathology of pulmonary hypertension. 2nd ed. New York: Wiley; 1977.
Wagenvoort CA, Mulder PGH. Thrombotic lesions in primary plexogenic arteriopathy: similar pathogenesis or complication? Chest. 1993;103(3):844–9.
D’Alonzo GE, Barst RJ, Ayres SM, Bergofsky EH, Brundage BH, Detre KM, et al. Survival in patients with primary pulmonary hypertension: results from a national prospective registry. Ann Intern Med. 1991;115(5):343–9.
Rubin LJ. Diagnosis and management of pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines. Chest. 2004;126(1 Suppl):7S–10S.
Simonneau G, Gatzoulis MA, Adatia I, Celermajer D, Denton C, Ghofrani A, et al. Updated clinical classification of pulmonary hypertension. J Am Coll Cardiol. 2013;62(25 Suppl):D34–41.
Rosenblum WD. Pulmonary arterial hypertension: pathobiology, diagnosis, treatment, and emerging therapies. Cardiol Rev. 2010;18(2):58–63.
Rubenfire M, Lippo G, Bodini BD, Blasi F, Allegra L, Bossone E. Evaluating health-related quality of life, work ability, and disability in pulmonary arterial hypertension: an unmet need. Chest Am Coll Chest Physicians. 2009;136(2):597–603.
Barst RJ, Rubin LJ, Long WA, Mcgoon MD, Rich S, Badesch DB, et al. A comparison of continuous intravenous epoprostenol (prostacyclin) with conventional therapy for primary pulmonary hypertension. N Engl J Med. 1996;334:296–301.
Pulido T, Adzerikho I, Channick RN, Delcroix M, Galiè N, Ghofrani H-A, et al. Macitentan and morbidity and mortality in pulmonary arterial hypertension. N Engl J Med. 2013;369:809–18.
Shafazand S, Goldstein MK, Doyle RL, Hlatky M a, Gould MK. Health-related quality of life in patients with pulmonary arterial hypertension. Chest. 2004;126(5):1452–9.
Mathai SC, Suber T, Khair RM, Kolb TM, Damico RL, Hassoun PM. Health-related quality of life and survival in pulmonary arterial hypertension. Ann Am Thorac Soc. 2016;13(1):31–9.
Fernandes CJCS, Martins BCS, Jardim CVP, Ciconelli RM, Morinaga LK, Breda AP, et al. Quality of life as a prognostic marker in pulmonary arterial hypertension. Health Qual Life Outcomes. 2014;12:130.
Gomberg-Maitland M, Thenappan T, Rizvi K, Chandra S, Meads DM, McKenna SP. United states validation of the Cambridge pulmonary hypertension outcome review (CAMPHOR). J Heart Lung Transplant. 2008;27(1):124–30.
Grünig E, Ehlken N, Ghofrani A, Staehler G, Meyer FJ, Juenger J, et al. Effect of exercise and respiratory training on clinical progression and survival in patients with severe chronic pulmonary hypertension. Respiration. 2011;81(5):394–401.
Taichman DB, Shin J, Hud L, Archer-Chicko C, Kaplan S, Sager JS, et al. Health-related quality of life in patients with pulmonary arterial hypertension. Respir Res. 2005;6:92.
Zlupko M, Harhay MO, Gallop R, Shin J, Archer-Chicko C, Patel R, et al. Evaluation of disease-specific health-related quality of life in patients with pulmonary arterial hypertension. Respir Med. 2008;102(10):1431–8.
Chen H, De Marco T, Kobashigawa EA, Katz PP, Chang VW, Blanc PD. Comparison of cardiac and pulmonary-specific quality-of-life measures in pulmonary arterial hypertension. Eur Respir J. 2011;38(3):608–16.
Ghofrani H-A, Galiè N, Grimminger F, Grünig E, Humbert M, Jing Z-C, et al. Riociguat for the treatment of pulmonary arterial hypertension. N Engl J Med. 2013;369(4):330–40.
Sastry BKS, Narasimhan C, Reddy NK, Raju BS. Clinical efficacy of sildenafil in primary pulmonary hypertension: a randomized, placebo-controlled, double-blind, crossover study. J Am Coll Cardiol. 2004;43(7):1149–53.
Matura LA, McDonough A, Carroll DL. Health-related quality of life and psychological states in patients with pulmonary arterial hypertension. J Cardiovasc Nurs. 2014;29(2):178–84.
Chua R, Keogh AM, Byth K, O’Loughlin A. Comparison and validation of three measures of quality of life in patients with pulmonary hypertension. Intern Med J. 2006;36(11):705–10.
Yorke J, Corris P, Gaine S, Gibbs JSR, Kiely DG, Harries C, et al. EmPHasis-10: development of a health-related quality of life measure in pulmonary hypertension. Eur Respir J. 2014;43(4):1106–13.
ClinicalTrials.gov. Clinical Study of Macitentan in Patients With Pulmonary Arterial Hypertension to Psychometrically Validate the PAH-SYMPACT Instrument. 2013. https://clinicaltrials.gov/ct2/show/NCT01841762.
Velanovich V. Comparison of generic (SF-36) vs. disease-specific (GERD-HRQL) quality-of-life scales for gastroesophageal reflux disease. J Gastrointest Surg. 1998;2(2):141–5.
Bessette L, Sangha O, Kuntz KM, Keller RB, Lew RA, Fossel AH, et al. Comparative responsiveness of generic versus disease-specific and weighted versus unweighted health status measures in carpal tunnel syndrome. Med Care. 1998;36(4):491–502.
Jenkinson C, Gray A, Doll H, Lawrence K, Keoghane S, Layte R. Evaluation of index and profile measures of health status in a randomized controlled trial. Comparison of the medical outcomes study 36-item short form health survey, EuroQol, and disease specific measures. Med Care. 1997;35(11):1109–18.
Weldam SWM, Schuurmans MJ, Liu R, Lammers J-WJ. Evaluation of quality of life instruments for use in COPD care and research: a systematic review. Int J Nurs Stud. 2013;50(5):688–707.
Puhan MA, Guyatt GH, Goldstein R, Mador J, Mckim D, Stahl E, et al. Relative responsiveness of the chronic respiratory questionnaire, St. Georges respiratory questionnaire and four other health-related quality of life instruments for patients with chronic lung disease. Respir Med. 2007;101(2):308–16.
Wiebe S, Guyatt G, Weaver B, Matijevic S, Sidwell C. Comparative responsiveness of generic and specific quality-of-life instruments. J Clin Epidemiol. 2003;56(1):52–60.
McKenna SP, Doughty N, Meads DM, Doward LC, Pepke-Zaba J. The Cambridge pulmonary hypertension outcome review (CAMPHOR): a measure of health-related quality of life and quality of life for patients with pulmonary hypertension. Qual Life Res. 2006;15(1):103–15.
Coffin D, Duval K, Martel S, Granton J, Lefebvre M-C, Meads DM, et al. Adaptation of the Cambridge pulmonary hypertension outcome review (CAMPHOR) into French-Canadian and English-Canadian. Can Respir J. 2008;15(2):77–83.
Ganderton L, Jenkins S, McKenna SP, Gain K, Fowler R, Twiss J, et al. Validation of the Cambridge pulmonary hypertension outcome review (CAMPHOR) for the Australian and New Zealand population. Respirology. 2011;16(8):1235–40.
Selimovic N, Rundqvist B, Kjörk E, Viriden J, Twiss J, McKenna SP. Adaptation and validation of the Cambridge pulmonary hypertension outcome review for Sweden. Scand J Public Health. 2012;40(8):777–83.
Cima K, Twiss J, Speich R, McKenna SP, Grünig E, Kähler CM, et al. The German adaptation of the Cambridge pulmonary hypertension outcome review (CAMPHOR). Health Qual Life Outcomes. 2012;10:110.
Galie N, Humbert M, Vachiery JL, Gibbs S, Lang I, Torbicki A, et al. ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension: The Joint Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS). 2015. http://dx.doi.org/10.1093/eurheartj/ehv317.
McKenna SP, Ratcliffe J, Meads DM, Brazier JE. Development and validation of a preference based measure derived from the Cambridge pulmonary hypertension outcome review (CAMPHOR) for use in cost utility analyses. Health Qual Life Outcomes. 2008;6:65.
The authors would like to thank Diana Oliveira, Filipe Campos and Pedro Batista for their collaboration in the translation process and Cognitive Debriefing Interviews, Tiago Campos (ARC Publishing) for writing support, and all patients participating in the study.
AR and LA contributed to study design, language translation, data collection, statistical analysis and manuscript writing. JT and SM contributed to language translation, statistical analysis and critical revision of the manuscript. MV contributed to data collection, statistical analysis and critical revision of the manuscript. FB, LC, JM and AM contributed to data collection and critical revision of the manuscript. All authors read and approved the final manuscript.
The authors declare no conflict of interest.
Supplementary Table 1. Item reliability statistics for Symptoms scale. Supplementary Table 2. Item reliability statistics for Activities scale. Supplementary Table 3. Item reliability statistics for Quality of life (QoL) scale. (DOC 294 kb)
About this article
Cite this article
Reis, A., Twiss, J., Vicente, M. et al. Portuguese validation of the Cambridge pulmonary hypertension outcome review (CAMPHOR) questionnaire. Health Qual Life Outcomes 14, 110 (2016). https://doi.org/10.1186/s12955-016-0513-8
- Pulmonary hypertension
- Precapillary pulmonary hypertension
- Pulmonary arterial hypertension
- Quality of life
- Portuguese adaptation
- Nottingham Health Profile