Table
2 shows the prevalence of chronic conditions among participants as well as the mean EQ-5D-5L utility and EQ-VAS scores by common chronic conditions. Approximately 32% of the participants had at least one chronic condition. The mean ± SD utility and EQ-VAS scores were 0.85 ± 0.14 and 76.73 ± 16.55 in the participants without any chronic conditions. The scores were 0.69 ± 0.17 and 61.14 ± 20.61 in the participants with chronic conditions. The most common conditions were psychological problems, including anxiety/nerves and depression (11.89%), osteoarthritis (7.22%), heart disease (6.40%), hypertension (6.8%), and diabetes (5.62%). The utility scores were the lowest in stroke (0.54) and cancer (0.58), while they were the highest in thyroid disease (0.70).
Table 2
Mean EQ-5D-5L utility and EQ-VAS scores by common chronic conditions
Without any chronic condition | 1945 | 63.54 | 0.86 | 0.14 | 77.50 | 16.14 |
With chronic condition | 1115 | 36.46 | 0.69 | 0.17 | 61.61 | 20.39 |
Anxiety/nerves | 231 | 7.55 | 0.66 | 0.17 | 59.57 | 22.34 |
Osteoarthritis | 221 | 7.22 | 0.62 | 0.15 | 59.44 | 20.35 |
Heart disease | 196 | 6.40 | 0.67 | 0.17 | 58.49 | 19.97 |
Hypertension | 186 | 6.08 | 0.65 | 0.17 | 58.04 | 21.91 |
Diabetes | 172 | 5.62 | 0.67 | 0.18 | 57.64 | 21.67 |
Insomnia | 145 | 4.74 | 0.68 | 0.19 | 60.61 | 22.58 |
Depression | 133 | 4.34 | 0.66 | 0.16 | 58.82 | 22.76 |
Breathing problems | 60 | 1.96 | 0.67 | 0.19 | 60.03 | 19.81 |
Lumbar disc hernia | 44 | 1.44 | 0.65 | 0.16 | 61.67 | 19.71 |
Digestive diseases | 22 | 0.72 | 0.68 | 0.12 | 58.41 | 16.06 |
Cancer | 19 | 0.62 | 0.58 | 0.25 | 50.32 | 30.07 |
Stroke | 15 | 0.49 | 0.54 | 0.12 | 47.86 | 12.97 |
Thyroid disease | 15 | 0.49 | 0.70 | 0.12 | 70.13 | 19.46 |
Other | 117 | 3.82 | 0.67 | 0.18 | 58.69 | 21.73 |
Table
3 shows the impact of chronic conditions on the HRQoL. The estimated coefficients were negative and statistically significant for all conditions except for insomnia and Thyroid disease. Stroke and cancer cause the most reduction in the HRQoL scores, which shows 0.204 and 0.177 reductions in the EQ-5D-5L utility scores and 18.11 and 17.31 reductions in EQ-VAS scores, respectively. According to model 1, lumbar disc hernia, digestive diseases, osteoarthritis, breathing problems, and anxiety/nerves cause 0.133, 0.109, 0.108, 0.087, and 0.078 reductions, respectively, in the EQ-5D-5L utility scores. According to model 2, digestive diseases, other diseases, lumbar disc hernia, breathing problems, and diabetes cause 12.42, 10.01, 8.45, 7.80, and 7.55 reductions in the EQ-VAS scores.
Table 3
The results of linear regression estimation to determine the impact of chronic diseases on HRQoL
Gender (female) | − 0.024* | 0.009 | − 0.40 | 1.01 |
Age (year) | − 0.002* | 0.000 | − 0.16* | 0.03 |
Years of schooling | 0.003* | 0.001 | 0.33* | 0.08 |
Employment status |
Employed | Ref | | Ref | |
Student | − 0.007 | 0.010 | 1.25 | 1.30 |
Home maker | − 0.028* | 0.010 | − 1.92 | 1.17 |
Retired | 0.015 | 0.010 | 3.04* | 1.25 |
Unemployed | − 0.018 | 0.015 | 1.36 | 1.92 |
Others | − 0.091* | 0.042 | − 10.56 | 6.01 |
Marital status |
Never married | Ref | | Ref | |
Married | − 0.010 | 0.008 | − 0.47 | 1.07 |
Divorce or widowed | − 0.046* | 0.016 | − 5.79* | 2.11 |
Anxiety/nerves | − 0.078* | 0.011 | − 7.09* | 1.53 |
Osteoarthritis | − 0.108* | 0.010 | − 5.68* | 1.41 |
Heart disease | − 0.067* | 0.012 | − 7.20* | 1.50 |
Hypertension | − 0.054* | 0.012 | − 4.79* | 1.65 |
Diabetes | − 0.052* | 0.014 | − 7.55* | 1.78 |
Insomnia | − 0.022 | 0.014 | − 2.43 | 1.88 |
Depression | − 0.074* | 0.013 | − 6.78* | 2.10 |
Breathing problems | − 0.087* | 0.022 | − 7.80* | 2.49 |
Lumbar disc hernia | − 0.133* | 0.025 | − 8.45* | 3.03 |
Digestive diseases | − 0.109* | 0.029 | − 12.42* | 3.46 |
Cancer | − 0.177* | 0.058 | − 17.31* | 7.17 |
Stroke | − 0.204* | 0.036 | − 18.11* | 3.44 |
Thyroid disease | − 0.045 | 0.034 | 1.09 | 5.27 |
Other | − 0.097* | 0.016 | − 10.01* | 1.97 |
Intercept | 0.938* | 0.018 | 80.29* | 2.20 |
Number of observations | 3041 | 3024 |
Adjusted R2 | 0.307 | 0.199 |
F statistic | 57.35* | 25.22* |
Discussion
In this study, we investigated the effect of chronic conditions on the HRQoL scores. The mean ± SD utility and EQ-VAS scores were 0.85 ± 0.14 and 76.73 ± 16.55 in the participants without any chronic condition while the scores were 0.69 ± 0.17 and 61.14 ± 20.61 in the participants with chronic condition. The results showed that common chronic conditions had significant negative effects on the HRQoL scores. Stroke (0.204 ± 0.036), cancer (0.177 ± 0.58), lumbar disc hernia (0.133 ± 0.025), digestive diseases (0.109 ± 0.029), osteoarthritis (0.108 ± 0.010) caused the most reductions in the HRQoL scores. The mean HRQoL scores were the lowest among individuals with stroke (0.54 ± 0.12), cancer (0.58 ± 0.25), and osteoarthritis (0.62 ± 0.15) diseases.
Previous studies showed that common chronic diseases have major effects on the HRQoL, which are similar to ours [
25‐
28]. However, due to the differences in individuals' preferences in different societies, the size of the effect of chronic diseases on the HRQoL may vary. A study in an elderly community-dwelling population in England showed the effects of common chronic diseases on the HRQoL using the EQ-5D questionnaire. The results suggested that most of these diseases reduce the HRQoL scores. Depression ( − 0.269, P < 0.001), neurological disease ( − 0.172, P < 0.0001), and osteoarthritis ( − 0.081, P = 0.0006) caused the greatest effects on the utility scores [
26]. The results of a study on Sweden general population demonstrated that the HRQoL weighs were the lowest among individuals with depression, stroke, and low back pain. The scores were (0.38 ± 0.026), (0.44 ± 0.035), and (0.55 ± 0.011) in people with these diseases. Regression analysis showed that depression, low back pain, and stroke caused (0.4305 ± 0.0270), (0.2810 ± 0.0105), and (0.2743 ± 0.0366) reductions in the HRQoL (P < 0.0001) [
25]. Another study on the general population in Finland showed that Parkinson's disease, anxiety disorders, arthrosis of the hip and knee, and depressive disorders were the most disabling chronic conditions based on EQ-5D, causing (0.201 ± 0.063), (0.169 ± 0.019), (0.155 ± 0.010), and (0.139 ± 0.016) reductions in mean utility scores, respectively. The mean utility scores were the lowest among individuals with Parkinson’s disease (0.440 ± 0.068), heart failure (0.585 ± 0.017), and stroke (0.587 ± 0.023) [
29].
A study in Hong Kong using the EQ-5D-5L questionnaire included four chronic diseases as an independent variable, whose effects were statistically significant on the HRQoL. The mean utility score for heart disease, hypertension, diabetes, and cancer was 0.88, 0.88, 0.87, and 0.87, respectively. In our study, these scores were 0.67, 0.65, 0.67, and 0.58, according to the Iranian crosswalk-based value set. The figures indicated that these diseases induced greater loss in Iranian HRQoL scores than the Chinese scores [
30].
The present study, for the first time, measured the association between chronic conditions and HRQoL via the EQ-5D-5L questionnaire in Iran. The EQ-5D-5L questionnaire is a general, reliable, and convenient measurement tool applied in the surveys of different diseases [
30].
The main limitation of this study was the fact that we measured the prevalence of chronic diseases based on self-reporting. Although studies have shown the high degree of agreement between the actual prevalence of chronic diseases and people’s self-declaration [
31], this method is not completely accurate because some people might not be aware of their illness or its name. In this study, we only examined the net effect of each of the chronic conditions on health-related quality of life. Given that the number of chronic conditions was high, we did not examine the interaction between them. However, there may be an interaction between some diseases, such as diabetes and heart disease, and their combined effect could be more or less than the sum of their net effects. Another limitation relates to the method of calculating the utility score. It is better to use the specific value set of each questionnaire to extract the utility scores. Because the EQ-5D-5L value set is not still available for Iranian population, we used the crosswalk method.