R E S E A R C H P A P E R

Factors affecting health status in patients withchronic obstructive pulmonary disease

Ayse Cil Akinci RNAssociate Professor, Nursing Department, College of Health, Kirklareli University, Kirklareli, Turkey

Erkan Yildirim MDAssistant Professor, Chest Diseases Department, Luleburgaz State Hospital, Kirklareli, Turkey

Accepted for publication July 2012

Akinci AC, Yildirim E. International Journal of Nursing Practice 2013; 19: 31–38Factors affecting health status in patients with chronic obstructive pulmonary disease

The aim of this study is to determine the correlation between the quality of life (QOL) and subjective dyspnoea, subjectivefatigue, sleep quality, and the forced expiratory volume in first second (FEV1) % predicted value and collective contri-bution of these variables on QOL. The study was conducted with 102 patients. Pulmonary function tests (FEV1 %predicted value, FEV1/forced vital capacity), subjective dyspnoea, subjective fatigue, sleep quality were assessed. Therewere negative correlations between QOL total score and pulmonary function tests, positive correlations between QOLtotal score and subjective dyspnoea score, subjective fatigue and sleep quality total scores. In addition, subjectivedyspnoea, subjective fatigue and sleep quality total scores and FEV1 % predicted value accounted for 68.1% of the varianceon QOL. As a conclusion of these findings, it has been recommended that these variables should be considered whenplanning an approach towards improving the QOL in chronic obstructive pulmonary disease patients.

Key words: chronic obstructive pulmonary disease, dyspnoea, fatigue, quality of life, sleep.

INTRODUCTIONChronic obstructive pulmonary disease (COPD) is animportant cause of morbidity and mortality worldwideand a greater health problem than previously realized.1–3

COPD is a highly incapacitating chronic health problem,which not only affects physical functioning, but alsoleisure and professional activities as well as emotional andsexual relationships. COPD and associated symptoms,such as dyspnoea and fatigue restrict patients’ tolerancefor exercise, consequently having a major impact onpatients’ ability to carry out the daily activities, which

frequently result in a decline in the quality of life(QOL).4–6 Previous studies have reported that the QOL islow in patients with COPD.7–9 It is crucial to determinethe factors related to the QOL and their contribution tothe QOL in order to develop a care plan. However, it isunclear which symptoms and physiological measurementslead to decrease in QOL. Is it the single most severesymptom or is it the collective interaction among symp-toms that leads to the decrease in QOL? The three mostcommon physical symptoms, which are the most likelycauses of decline in QOL in this population, aredyspnoea,10–15 fatigue16–18 and sleep disturbance.19,20 Inaddition to these symptoms, the most common physi-ological measurement which affect QOL in a negative wayis the forced expiratory volume in first second (FEV1) %predicted value.10,11,13,21–23 Although, these variables are

Correspondence: Ayse Cil Akinci, Karaca Ibrahim Mah, Nuzhet SomayCad, Itfaye Yani, Taskin Sitesi, B Blok 3/6, Kirklareli 39100, Turkey.Email: aysecil2003@yahoo.co.uk

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International Journal of Nursing Practice 2013; 19: 31–38

doi:10.1111/ijn.12034 © 2013 Wiley Publishing Asia Pty Ltd

related to the QOL, many researchers have explored thecollective contribution of these variables on QOL inpatients with COPD. The aim of is this study is to deter-mine the correlation between QOL and subjectivedyspnoea, subjective fatigue, sleep quality, and FEV1 %predicted value and collective contribution of these vari-ables on QOL.

METHODSSample

The sample of the study consisted of 102 patients whowere referred to Luleburgaz State Hospital, ChestDiseases Outpatient Clinic between October 2010 andMay 2011 and who met the inclusion criteria as wellas accepted participation in the study. Among the 102participants, only 79 completed tests of respiratory func-tioning whereas all of the participants completed themeasurement instruments. Because the spirometer wasout of order, pulmonary function tests were not appliedto all of the participants.

Inclusion criteriaHaving a COPD diagnosis according to the Global Initia-tive for Chronic Obstructive Lung Disease criteria andnot having a history of acute exacerbation that requiresoutpatient or inpatient intervention were the inclusioncriteria.

Exclusion criteriaExclusion criteria include having uncontrollable hyper-tension and diabetes, ischaemic heart disease, congestiveheart failure, cerebrovascular disease, cancer, psychiatricdisorder, neurological diseases or diseases of the muscle-skeleton system, liver failure and kidney failure. It hasbeen hypothesized that these diseases could have a nega-tive impact on QOL, so the patients with such diseaseswere not involved in the study.

Data collection processThe data were collected in the Chest Diseases OutpatientClinic. While collecting data from the patients, firstlypulmonary function tests were performed. Then the sub-jective dyspnoea level, sleep quality, subjective fatigueand QOL of the patients were assessed through scales.The average time for collecting data for each patient wasabout 30–40 min.

Pulmonary function tests were performed with a spiro-meter (ZAN 100 handy, nSpire Health, Inc., Longmont,

USA) according to the criteria set by the American Tho-racic Society. FEV1 % predicted value and FEV1/forcedvital capacity (FVC) ratio were measured in these tests.

Measurement instrumentsThe level of subjective dyspnoea was assessed with theModified Medical Research Council (MRC) DyspneaScale; sleep quality was assessed with the Pittsburgh SleepQuality Index (PSQI); subjective fatigue was assessed withthe Piper Fatigue Scale (PFS); and the QOL was assessedwith disease-specific QOL scale (St. George’s RespiratoryDiseases Questionnaire (SGRQ) ).

The MRC Dyspnea Scale is a five-point scale based ondegrees of various physical activities that precipitatebreathlessness. MRC scores range from 0 (not troubledwith breathlessness except with strenuous exercise) to 4(too breathless to leave the house or breathless whiledressing or undressing).14,24 This validated scale is widelyused to evaluate dyspnoea in the studies carried out atTurkey25,26 and other countries.14,24

The PFS contains 22 items that measure four sub-dimensions of subjective fatigue: behavioural/severity,affective/meaning, sensory and cognitive/mood. Eachitem is determined by two words (e.g. strong/weak), andthe participant circles a number from 0 (weak) to 10(strong) that best describes the current personal fatigueexperience. Total and sub-dimension mean scores areobtained by summing the individual items of each sub-dimension and dividing by the number of items in thesub-dimension or total score. PFS total score range from0 to 10. As the levels of subjects’ fatigue increase, the PFSscore also increases. Five open-ended questions regardingthe temporal dimension of fatigue, perceived cause, effectand additional symptoms complete the PFS. These fivequestions are not used for calculating PFS scores.27 Thisscale’s reliability and validity were tested by Can and theCronbach’s alpha coefficient of the full scale was reportedto be 0.94.28 In this study, the Cronbach’s alpha coeffi-cient of the full scale was 0.887.

PSQI is a self-report questionnaire that assesses sleepquality and quantity. The original version was designed tomeasure sleep reports over a 1-month interval. The PSQI iscomposed of 19 self-rated questions and five questionsrated by a bed partner or roommate (only the self-rateditems are used in to score the scale). The 19-item self-report questionnaire consists of seven sub-dimensionsscores: subjective sleep quality, sleep latency, duration,habitual sleep efficiency, sleep disturbances, use of sleeping

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medication and daytime dysfunction. Each sub-dimensionsscore ranges from 0 (no difficulty) to 3 (severe difficulty).The score of each sub-dimensions is summed to produce atotal score (range of 0–21). A PSQI total score of > 5 isconsidered to be a sign of significant sleep disturbance.Additional questions completed by a bed partner are notused in the scoring.29,30 This scale’s reliability and validitywere tested by Agargun and colleagues, and the Cron-bach’s alpha coefficient of the full scale was reported to be0.80.31 In this study, the Cronbach’s alpha coefficient ofthe full scale was 0.764.

SGRQ, which is a disease-specific QOL questionnaire,contains 76 items and measures three sub-dimensions:symptoms, activity and impacts. SGRQ scores rangefrom 0 (perfect health) to 100 (worst possible state).Validity and reliability for the Turkish population wasmade by Durna and Ozcan and the Cronbach’s alpha coef-ficient of the symptoms, activity and impacts was reportedto be 0.86, 0.88 and 0.86, respectively.32 In this study,the Cronbach’s alpha coefficient of the full scale was0.807.

Ethical issuesBecause of the absence of the ethical committee atKırklareli city, related permissions received from theKırklareli Health Directorate and study was arranged

according to the Helsinki Declaration.33 All patients wereinformed about the procedures of the proposed study andwritten consents are taken.

Statistical analysisThe statistical analysis was performed by using the Statis-tical Package for the Social Sciences for Windows version15.0.34 During this analysis of the data, descriptivestatistics were computed according to the patients’characteristics. Relationship between QOL and pulmo-nary function tests, subjective dyspnoea, subjectivefatigue and sleep quality were evaluated using Pearsoncorrelation analysis. While evaluating collective contribu-tion of subjective dyspnoea, subjective fatigue, sleepquality, FEV1 % predicted value, age, gender, educationalstatus and duration of disease on QOL, linear regressionanalysis was used. QOL total scale score was determinedas dependent variable, and subjective dyspnoea, subjec-tive fatigue, sleep quality, FEV1 % predicted value, age,gender, educational status and duration of disease weredetermined as independent variables. For all analysis, sta-tistical significance was determined at the 5% level with95% confidence intervals.

RESULTSocio-demographic characteristics and illness-related vari-ables of the subjects are presented in Table 1. The mean

Table 1 Socio-demographic characteristics and illness-related variables of the subjects (n = 102)

Variables n % Mean � SD Range

Age (Year) 66.8 � 10.0 (43–86)Sex Female 11 13.9

Male 68 86.1Education Literate 5 6.3

1–8 years 66 83.58–11 years 3 3.8> 11 years 5 6.3

Marital status Married 62 78.5Single 17 21.5

Disease duration (Year) 9.1 � 8.5 (0.5–30)Smoking User 13 16.5

Quit 59 74.7Never used 7 8.9

Oxygen use User 5 6.3Non-user 74 93.7

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age of the subjects was 66.8 years, 86.1% were male and83.5% received education for 1–8 years. The mean dura-tion of COPD was 9.1 years, 74.7% of the patients hadquit smoking in the past and 93.7% do not use oxygen inthe present. Table 1 presents other findings related to thepatients.

Among the respiratory function tests, the FEV1 % pre-dicted value and the FEV1/FVC ratio were 51.5 and63.4%, respectively. Average MRC dyspnoea score,which was found 2.3 (0–4), indicated that the patients’dyspnoea level was moderate. Average PFS total score,which was found 4.3 (0.14–8.48), indicated that thepatients’ fatigue was moderate/low level. The mostaffected sub-dimension was affective/meaning and theleast affected sub-dimension was cognitive/mood in PFS.Average PSQI total score, which was found 7.1 (1–19),indicated that the patients had significant sleep distur-bance. The most affected sub-dimension was sleep distur-bances and the least affected sub-dimension was use of

sleeping medication in PSQI. Average SGRQ total scorewhich was found 58.7 (16–91), indicated that thepatients’ QOL was moderate/low level. The mostaffected sub-dimension was impacts and the least affectedsub-dimension was activity in SGRQ. Table 2 presentsother related findings.

The relationship between SGRQ and pulmonary func-tion tests, MRC, PFS and PSQI were given in Table 3.There were weak negative correlations between SGRQtotal score and FEV1 % predicted value and FEV1/FVC.All sub-dimensions scores and total score of SGRQ werepositively and strongly correlated with the MRC score.Impact, activity and SGRG total scores were positivelyand strongly correlated with the sub-dimension scores andPFS total scores. Subjective sleep quality of PSQI waspositively and strongly/moderately correlated with theimpacts sub-dimension and SGRQ total scores. Sleep dis-turbances and daytime dysfunction sub-dimension scoresand PSQI total score was positively and strongly/

Table 2 Pulmonary function tests, MRC, PFS, PSQI and SGRQ scores of the subjects

Variables Mean SD Range

Pulmonary function tests

(n = 79)

FEV1 (% predicted value) 51.5 16.1 (18–80)FEV1/FVC (%) 63.4 9.3 (34.6–70.2)

MRC (n = 102) 2.3 1.2 (0–4)PFS (n = 102) Behavioural/severity 4.6 2.2 (0–8.8)

Affective/meaning 4.9 4.4 (0–9)Sensory 4.5 2.5 (0–9.8)Cognitive/mood 3.0 2.2 (0–8.17)Total 4.3 2.0 (0.14–8.48)

PSQI (n = 102) Subjective sleep quality 1.3 0.6 (0–3)Sleep latency 1.1 0.9 (0–3)Duration 0.8 1.0 (0–3)Habitual sleep efficiency 0.7 1.0 (0–3)Sleep disturbances 1.6 0.6 (0–3)Use of sleeping medication 0.4 0.9 (0–3)Daytime dysfunction 1.2 0.8 (0–3)Total 7.1 3.9 (1–19)

SGRQ (n = 102) Symptoms 57.9 17.5 (17–93)Activity 75.0 21.8 (0–100)Impacts 49.7 17.1 (10–91)Total 58.7 16.4 (16–91)

Higher MRC scores indicate worse dyspnea level. Higher PFS scores indicate increased fatigue. Higher PSQI scores indicate worse sleep

quality and quantity. Higher SGRQ scores (symptoms, activity and impacts) indicate worse QOL. FEV1 %, forced expiratory volume in

first second ; FVC, forced vital capacity; MRC, Medical Research Council; PFS, Piper Fatigue Scale; PSQI, Pittsburgh Sleep Quality Index;

QOL, quality of life; SGRQ, St. George’s Respiratory Diseases Questionnaire.

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moderately correlated with impacts and activity sub-dimensions scores and SGRQ total score.

MRC score, PFS and PSQI total scores, FEV1% pre-dicted value, age, gender, educational status and dura-tion of disease accounted for 68.1% of the variance onSGRQ in patients with COPD. Although MRC score,PFS and PSQI total scores and FEV1 % predicted valuehave significant contribution on SGRQ, other variablessuch as age, gender, educational status and duration ofdisease have no significant contribution on SGRQ(Tables 4,5).

DISCUSSIONThe study showed that the QOL decreased with theincrease in dyspnoea, fatigue and sleep disturbance, andwith the decrease in FEV1 % predicted value and FEV1/FVC in patients with COPD. In addition to this dyspnoea,fatigue, sleep disturbance and FEV1 % predicted valueaccounted for 68.1% of the variance on QOL.

The relationship between QOLand dyspnoea

According to the study, positive strong correlations werefound between the QOL sub-dimensions and total scoreand subjective dyspnoea score. Similar to our findings, ithas been suggested that the QOL decreased with theincreased level of dyspnoea.13–15 Another study reportedthat the dyspnoea score showed a positive correlation withthe QOL total score and activity sub-dimension score.11

In conclusion, our study demonstrates that the QOL inpatients with COPD, decreases as the level of dyspnoeaincreases.

The relationship between QOLand fatigue

In our study, strong positive correlations between QOLsub-dimensions and total score and fatigue total score arefound. Findings from other studies seem to support theseresults. All sub-dimensions of fatigue (general, physical,reduced activity, reduced motivation and mental) have

Table 3 The relation between SGRQ and pulmonary function tests, MRC, PFS and PSQI scores

Variables SGRQ

Symptoms Impacts Activity Total

Pulmonary Function Tests

(n = 79)

FEV1 (% predicted value) -0.032 -0.296** -0.276* -0.280*FEV1/FVC (%) -0.131 -0.218 -0.271* -0.253*

MRC (n = 102) 0.388*** 0.568*** 0.593*** 0.622***PFS (n = 102) Behavioural/severity 0.348** 0.716*** 0.744*** 0.757***

Affective/meaning 0.183 0.374** 0.405*** 0.402***Sensory 0.293** 0.538*** 0.491*** 0.547***Cognitive/mood 0.211 0.437*** 0.368** 0.427***Total 0.299** 0.597*** 0.579*** 0.616***

PSQI (n = 102) Subjective sleep quality 0.296** 0.412*** 0.349** 0.421***Sleep latency 0.200 0.350** 0.198 0.309**Duration 0.230* 0.176 0.199 0.218Habitual sleep efficiency 0.231* 0.228* 0.257* 0.271*Sleep disturbances 0.255* 0.509*** 0.384*** 0.481***Use of sleeping medication -0.042 0.066 0.004 0.031Daytime dysfunction 0.213 0.331** 0.446*** 0.400***Total 0.287* 0.413*** 0.369** 0.428***

*** P < 0.001, ** P < 0.01, * P < 0.05. Higher MRC scores indicate worse dyspnoea level. Higher PFS scores indicate increased fatigue.

Higher PSQI scores indicate worse sleep quality and quantity. Higher SGRQ scores (symptoms, activity and impacts) indicate worse QOL.

FEV1 %, forced expiratory volume in first second ; FVC, forced vital capacity; MRC, Medical Research Council; PFS, Piper Fatigue Scale;

PSQI, Pittsburgh Sleep Quality Index; QOL, quality of life; SGRQ, St. George’s Respiratory Diseases Questionnaire.

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been found to be correlated with the QOL total score16

and the Manchester COPD fatigue scale total score cor-related with the QOL total score.17 In addition, it has beenfound that subjects who reported poor health status hadhigher levels of fatigue.18 Our study demonstrated thatthere is a correlation between the level of fatigue andQOL in patients with COPD and that patients’ QOLdecreased as the level of fatigue increased.

The relationship between QOL andsleep quality

In this study, there were positive correlations betweenQOL sub-dimensions and total score and PSQI totalscore. Similar to our study, it has been reported that theQOL total score correlated with the PSQI total score.19 Inaddition, it has been reported that the QOL total scorecorrelated with the sleep disturbances and daytime func-tioning sub-dimensions of the sleep quality index score inCOPD patients with co-morbid anxiety or depression.20

In conclusion, this study confirmed the correlation

between the quality of sleep and the QOL in patients withCOPD and that the QOL decreased with the quality ofsleep.

The relationship between QOL andpulmonary function tests

In this study, there were negative weak correlationsbetween SGRQ total score and FEV1 % predicted valueand FEV1/FVC. The results of studies investigatingthe relationship between the QOL and FEV1 are incon-sistent. There are studies reporting a negative correlationbetween FEV1 % predicted value and QOL scores10,21–23

and a decrease in QOL scores with an increase of diseasestage,11,13which is consistent with our findings.

On the other hand, some studies reported that therewas no relationship between QOL scores and FEV1,which is contrary to our results.20,35 In our study, wedetermined that there is a negative correlation betweenthe QOL total score and FEV1 % predicted value but thiscorrelation was found to be weak.

Table 4 The result of the linear regression analysis

Unstandardized coefficients Standardized coefficient t P

Coefficient Standard error ß

Constant 32.466 12.142 2.674 0.009MRC 4.987 1.023 0.372 4.877 0.000PFS 3.281 0.602 0.404 5.454 0.000PSQI 0.870 0.313 0.206 2.775 0.007FEV1 (% predicted value) -0.179 0.075 -0.175 -2.377 0.020Age 0.146 0.125 0.089 1.172 0.245Gender 0.389 3.378 0.008 0.115 0.909Educational status -2.295 1.601 -0.103 -1.434 0.156Duration of disease 0.010 0.144 0.005 0.071 0.944

Note: R2 = 0.681 (P < 0.001). FEV1 %, forced expiratory volume in first second ; MRC, Medical Research Council; PFS, Piper Fatigue

Scale; PSQI, Pittsburgh Sleep Quality Index.

Table 5 The model statistic of regression analysis

Model Sum of squares df Mean square F P

Regression 14 435.372 8 1804.422 18.701 0.000Residual 6 754.045 70 96.486 — —Total 21 189.418 78 — — —

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Collective contribution of dyspnoea,fatigue, sleep quality and

FEV1 % value on QOLIt has been determined with this study that dyspnoea,fatigue, sleep disturbance and FEV1 % predicted valueaccounted for 68.1% of the variance on the quality oflife. Our results are consistent with other studies. Forexample, it has been reported that FEV1 is the mostimportant factor in the decrease of QOL36 and also indetermining the activity dimension of the QOL.37 Otherimportant predictors of QOL in patients with COPD arebaseline dyspnoea,38 quality of sleep and FEV1 % pre-dicted value,19 quality of sleep total score and FEV1 %predicted value,39 sleep quality and physical fatigue symp-toms.40 In addition, dyspnoea in mild COPD, dyspnoeaand anxiety in moderate COPD, and dyspnoea and FEV1

in severe COPD13 are important predictors of QOL.Finally, in another study, the level of dyspnoea and FEV1

% predicted value were found to be the independentpredictors of some sub-dimensions of the general QOLscale.41 In conclusion, it has been confirmed that dysp-noea, fatigue, sleep quality and FEV1 % predicted valuehave a collective contribution on the QOL in patientswith COPD.

Study limitationsWe should mention some limitations of the present study.Because we recruited only stable patients from the outpa-tient clinic, the study sample might not be representativeof patients with severe COPD who are incapable ofmaking regular visits. Second, other factors such asactivity level, psychological/psychiatric problems andco-morbid diseases, which might affect quality of life,were not examined. It is suggested that in further studies,this factors should be evaluated.

CONCLUSION AND SUGGESTIONIn this study, it has been found that the QOL was associ-ated with dyspnoea, fatigue, sleep, FEV1 % predictedvalue and FEV1/FVC in patients with COPD. In addi-tion, these variables accounted for 68.1% of the varianceon QOL. According to these results, while planningapproaches that aim to increase the QOL in patients withCOPD, it has been suggested that dyspnoea, fatigue andsleep disturbance should be regulated and FEV1 % pre-dicted value should be increased.

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