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Waugh N, Royle P, Craigie I, et al. Screening for Cystic Fibrosis-Related Diabetes: A Systematic Review. Southampton (UK): NIHR Journals Library; 2012 May. (Health Technology Assessment, No. 16.24.)

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Screening for Cystic Fibrosis-Related Diabetes: A Systematic Review.

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Appendix 6Quality-of-life studies not mentioning cystic fibrosis-related diabetes but with cystic fibrosis-specific measures

Cystic Fibrosis Questionnaire

Several studies have used the CFQ. The origins of this are reported by Quittner et al.231 CFQ is a disease-specific measure (or rather ‘measures’, as there are versions for children, parents and adults).

Riekert et al.232 examined associations between lung function, depression and QoL in adults with CF, using:

  • FEV divided into good (≥ 70%) and poor (< 70% predicted)
  • depression as reported by Beck Depression Inventory (BDI) score 0–63 (high is bad)
  • CFQ teenagers and adults score 0–100 (high is better).

They had a 57% response rate among 133 eligible adults, mean age 31 years (range 19–65 years) of whom 26% had CFRD. Unfortunately, no results were given separately. The mean FEV was 63% (range 21–116%) of predicted, with 62% < 70%.

Thirty per cent screened positive for depression (BDI score > 10).

The CFQ results were proportional to depression scores and to FEV. There was a clear association between QoL and lung function.

Urquhart et al.233 used CFQ-UK to assess the effects of lung function and exercise capacity on QoL in 35 children aged 11–15 years. The correlation between QoL and lung function tests was weak, but there was a stronger correlation (r2 = 0.4) with exercise capacity (VO2 peak).

Thomas et al.234 used CFQ and a generic health status measure [Pediatric Quality of Life Inventory (PedsQL)] to compare outcomes in patients looked after in a city centre clinic and in country areas, but they also reported the association of QoL and lung function. Thirty-three teenagers had results suggesting a decline in lung function with age, and this correlated with QoL as reflected in the CFQ. There was no correlation with lung function in younger children, but they showed very little decline in lung function. The authors attribute the lack of correlation to the good lung function in younger children.

Klijn et al.235 set out to validate the Dutch version of the CFQ but also provide data comparing results in mild (FEV > 70% predicted, mean was 89%), moderate (FEV 41–70% predicted, mean 56%) and severe disease (FEV < 41% predicted, mean 26%). There were clear differences in CFQ results among these groups but SDs were quite large. The biggest differences were in physical functioning, especially between moderate and severe disease. However, most differences were not statistically significant owing to the degree of scatter about the group means, raising doubts about the sensitivity of the CFQ for reflecting small changes in lung function.

The CFQ has also been validated in the USA by Quittner et al.,231 who also examined results after dividing patients into three groups by FEV, these groups having similar bands to those in the Dutch validation. Again, there were marked differences among these groups, most marked for physical functioning, role functioning and weight. The authors do not provide data on the statistical significance of differences in CFQ domains.

Cystic Fibrosis Quality of Life

Gee et al.236 used the CFQoL questionnaire to examine associations between various clinical variables and QoL in 223 patients, and this was one of the few studies to provide any data on the effect of CFRD. Those with CFRD (49 patients) had lower FEV (mean 41% predicted, 25–75 percentile, range 30–59) than those without (mean 55%, range 41–77). The diabetic and non-diabetic groups had similar BMIs (both 20 and 21 kg/m2) and ages (26 and 24 years).

The association between FEV and QoL was weak, and the authors conclude that large differences in FEV would be required before the CFQoL changed significantly.

Studies using generic health-status measures

Child Health Questionnaire

The CHQ covers 10 domains via 75 questions, and is designed to be used by both children and parents. It has a scale of 0 to 100, with high scores being better.

Powers et al.,237 from Massachusetts, set out to administer the CHQ to 39 adolescent patients, their mothers and fathers. The response rates were 82% for patients and mothers but only 64% for fathers. So final results are based on 24 triads. They found a moderate-to-strong relationship between FEV and QoL but only the correlation coefficient (0.73) is given, not the incremental relationship or the scatter about the regression line.

Britto et al.,238 from Ohio, also compared QoL with pulmonary function as measured by predicted FEV1 and with exercise capacity, in 63 children aged 5–17 years, using the CHQ. Patients aged > 18 years (48 patients) used the SF-36. Although QoL scores fell with %FEV1, the trend was not statistically significant. Nor was there any association between QoL and the 6-minute walk distance. The strongest determinant of QoL was recent pulmonary exacerbations.

Sawyer,239 from Adelaide, used CHQ in a follow-up study of children aged 10–16 years with diabetes (n = 44), asthma (n = 40) and CF (n = 39), recording results at baseline, 6, 12, 18 and 24 months. This allowed them to compare results of children with those from healthy children, and among the three diseases, and to look at time trends, albeit over a timescale short relative to life-time. They also used disease-specific measures, including the CFQoL. Over time, the physical health scores of the CF children declined from 65 to 56 (described as significant but no p-value given), whereas there was no change in the diabetic children, and those with asthma showed a non-significant improvement (55–60).

The same group240 asked parents to assess their children's QoL using CHQ and found that children with CF were less healthy than those with diabetes or asthma, and also that the CF children deteriorated. Children scored their QoL better than their parents did.

Another comparison of QoL among different childhood conditions was reported by Ingerski et al.241 The authors noted that QoL was poorer in children with CF than in healthy children, was about the same as in children with T1DM, but was better than in obese children.

Nottingham Health Profile

Congleton,242 from London, assessed QoL in 240 adults (> 16 years) with CF, using the Nottingham Health Profile, with a small CF supplement. They then compared the results with healthy people (from a community survey) and with people who had other conditions.

The patients with CF had significantly worse scores in energy, pain and social isolation (men) or pain, emotion and sleep (women). Men showed a decline with age compared with the general population, but women did not.

Both men and women reported more problems of daily living than the general population, with five scores of around 30% problem frequency in the men with CF compared with < 10% in the men in the community survey. There were similar, but fewer, marked increases in problems in women.

However, when the CF scores were compared with those from patients with other conditions, CF, surprisingly, came out better than pregnancy and peripheral vascular disease, and about the same as ‘minor non-acute conditions’ (such as varicose veins and hernias).

The Quality of Well-Being scale

The Quality of Well-Being (QWB) scale, which is not specific to any disease, was first validated for use in CF by Orenstein et al.243 in a mixed group of adults and children. However, Kotwicki and colleages244 found it less useful in children, although they did conclude that some children found the treatment worse than the disease.

Suri et al.245 used QWB in a treatment trial in a group of children, and also found it had short-comings, including that it was not sensitive to clinically meaningful changes and that it had ‘uncertain applicability to children and adolescents’.

European Quality of Life-5 Dimensions

The EQ-5D, sometimes also called the EuroQol, is a generic measure of health based on the five domains of mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each domain is scored on three levels, for no problems, some problems or severe problems, but there is also a visual analogue scale (VAS) option with a scale of 0 to 100. EQ-5D is the measure preferred by NICE because it can provide utilities for cost-effectiveness analysis. There is now a version for use in children: the EQ-5D-Y.

Eidt-Koch et al.,246 from four CF centres in Germany, carried out a study in which they administered both the EQ-5D-Y and the CFQ to 96 patients aged 8–17 years. They found good but not perfect correlations with the CFQ, suggesting that the EQ-5D-Y could be used for assessing changes in utility in young patients with CF. There was higher correlation with the VAS.

Other studies

From the Netherlands, de Jong et al.247 contribute a small study of 15 patients with CF and a control group. They report pulmonary function, exercise capacity, dyspnoea and QoL using the Sickness Impact Profile (SIP). They found marked effects on physical functioning scores (5.4 vs 0.7), but no significant difference in psychosocial ones (possibly because of numbers, because the scores were 2.65 and 1.04). SIP scores deteriorated as exercise capacity and dyspnoea scores did, but did not correlate with FEV1.

Bradley et al.248 from Belfast also reported little correlation between QoL and spirometric measures of lung function, this time using the Chronic Respiratory Disease Questionnaire, in a study concerned mainly with amending that tool for use in CF.

Goldbeck et al.,249 from Munchen, carried out a feasibility study to measure QoL in a CF clinic. (The authors note that the usual way of doing so is to ask ‘How are you?’) They set out to see if sequential measurement of QoL would be feasible, using the Questions on Life Satisfaction [FLZ(M)] questionnaire and doing so in parallel with lung function tests.

They studied 108 patients over 18 months, from an initial population of 148, all aged > 15 years. The interest from our perspective is what most determined QoL. There were correlations of QoL with acute infective exacerbations and colonisation with Pseudomonas. However, neither slow declines in pulmonary function nor FEV affected QoL. QoL was generally quite stable over the 18-month period.

Goldbeck and Schmitz250 compared the SF-36, the FLZ(M) (questions on life satisfaction) questionnaire and a QoL profile for chronic diseases (Quality-of-Life Profile) in 70 adolescents and adults with CF. They included a control group of healthy peers, which gives us data on the impact of CF on QoL. The SF-36 results showed poorer QoL in the CF adolescents on most dimensions, especially general health, physical functioning and vitality. There was little difference in mental health or social role functioning.

Weiner et al.,251 from Boston, carried out a literature review examining costs, QoL and compliance with treatment. The cost data are useful and are referred to elsewhere. They did not consider CFRD and it is not mentioned. Their main interest was in the use of antibiotics, particularly tobramycin, and the review was funded by Novartis, the manufacturer of tobramycin.

Cruz et al.252 reviewed the literature on anxiety and depression in CF, concluding that both were more common than in the general population, with anxiety commoner but depression probably more important. However, they also concluded that the body of evidence was based on too many small studies from single centres, using a wide range of instruments. The same group253 had reported that depression was commoner in people with CF and in parents of children with CF.

© 2012, Crown Copyright.

Included under terms of UK Non-commercial Government License.

Bookshelf ID: NBK98674


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