Diabetes mellitus is one of the most prevalent diseases worldwide. Diabetes is a chronic disease associated with micro- and macro-vascular complications and deterioration in general health status. Therefore, the aim of this study was to estimate general health status among Iranian diabetic patients through a systematic review and meta-analysis of study utilizing the Short-Form-36 questionnaire.
Methods
Searching the EMBASE, PubMed, ISI/Web of Sciences (WOS), MEDLINE via Ovid, PsycoINFO, as well as Iranian databases (MagIran, Iranmedex, and SID) from January 2000 to December 2017. The methodological quality of the studies was evaluated using the “A Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions” (ACROBAT-NRSI). Random-effect model was used and the means were reported with their 95% confidence interval (CI). To evaluate the heterogeneity between studies, I2 test was used. Egger’s regression test was used to assess the publication bias.
Results
Fourteen studies were retained in the final analysis. The mean general health status using SF-36 in diabetic patients of Iran was 51.9 (95% CI: 48.64 to 53.54). The mean physical component summary was 52.92 [95% CI: 49.46–56.38], while the mean mental component summary was 51.02 [95% CI: 46.87–55.16].
Conclusion
The findings of this study showed that general health status in Iranian diabetic patients is low. Health policymakers should work to improve the health status in these patients and take appropriate interventions.
A Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions
BP
Bodily pain
CI
Confidence intervals
ERF
Emotional role functioning
GHP
General health perceptions
MCS
Mental Component Summary
MeSH
Medical Subject Headings
MH
Mental health
PCS
Physical Component Summary
PF
Physical functioning
PRF
Physical role functioning
PROs
Patient-reported outcomes
SF-36
The Short-Form 36
SID
Scientific Information Database
SMD
Standardized Mean Difference
SRF
Social role functioning
VT
Vitality
WOS
Web of Science
Background
Diabetes mellitus is one of the most prevalent diseases worldwide, imposing a relevant epidemiological and clinical burden, both in terms of deaths and morbidities. The prevalence of diabetes is increasing both in developed and developing countries, and has doubled over the past three decades, with almost 80% of diabetic patients living in less developed countries [1, 2]. Population aging, lifestyle changes, lack of mobility, and many other factors characterizing modern life have contributed to such an increase [3]. In 2014, the prevalence of diabetes in people aged greater than 18 years in the world was about 8.5%. It is anticipated that diabetes will be the seventh cause of death by 2030, and, despite all efforts to control the disease, it still remains one of the major public health challenges [4]. The number of people with diabetes is expected to rise up to about 592 million by 2035 [5]. The prevalence of diabetes in the Middle East and North Africa is about 10.9%. In these areas, about 35 million people are affected by diabetes, with Iran having the highest prevalence (9.94%) among the countries of the Middle East [6].
Such concerns necessitate adequate health policies in order to control and prevent diabetes [7]. This disorder represents a chronic disease associated with micro- and macro-vascular complications, which dramatically impact on general health status [8]. Studies have shown that such complications can affect physical, mental and social life of people, modifying and interfering with their usual every day functioning [9]. Hence, treatments of diabetes are usually evaluated based on their effect on health status [10], which, as a key factor in effectiveness studies, refers, indeed, to the mental, physical and social status of the patient [11]. Considering the general health status among diabetic patients can provide care givers with a better understanding of patients’ conditions, indicating which health provisions are necessary for a proper management of the disease [12].
Anzeige
To assess general health status among diabetes patients, a variety of questionnaires have been developed that can measure different dimensions of the patients’ life. The Short-Form 36 (SF-36) questionnaire is one of the most commonly used instruments [13]. It includes 36 questions distributed across eight domains (namely, vitality, physical function, body pain, health perception, physical role, emotional role, social role and mental health) [14, 15].
Various studies have been conducted to assess Iranian diabetic population’s quality of life. Such information can be helpful for measuring the severity of complications and designing and implementing appropriate healthcare policies. In 2013, a review study was conducted in Iran on health status in diabetic patients. In this study, the assessment of health status of diabetics was based on all questionnaires used in Iran. Authors suggested that a meta-analysis study could better provide information about health status in diabetic patients [16]. Therefore, the aim of this study was to estimate general health status among Iranian diabetic patients through a systematic review and meta-analysis of studies utilizing a specific instrument, namely the SF-36 questionnaire.
Methods
Literature search
The current study has been performed according to the “The Meta-analysis of Observational Studies in Epidemiology” (MOOSE) guidelines [17]. (Additional file 1).
Two authors independently searched different scholarly electronic databases: namely, EMBASE, PubMed, ISI/Web of Sciences (WOS), MEDLINE via Ovid, PsycoINFO, as well as Iranian databases (MagIran, Iranmedex, and SID). These databases were systematically searched from January 2000 to December 2017 using the following search strategies: (“general health status”) AND (“Short form 36” OR “SF-36” OR “SF-36 health survey questionnaire” OR “Short form-36 health survey questionnaire”) AND (“Diabetes” OR “Diabetic”) AND “Iran”. Studies were searched both in English and Persian (no language filter applied). Reference lists of each included study were also scanned and hand-searched for possible related studies.
Anzeige
Inclusion/ criteria
Studies with the following criteria were included if: i) utilizing the SF-36 questionnaire for investigating general health status among Iranian populations, ii) reporting an average score for the eight domains of the questionnaire, iii) reporting both Physical Component Summary (PCS) and Mental Components Summary (MCS) indicators, and iv) reporting means with standard errors (SE) or standard deviations (SD). Both cross-sectional or case-control studies were considered.
Exclusion criteria
Studies were excluded if: i) designed as reviews, letters to the editor, editorials, expert opinions, commentaries, clinical trials, case-reports, case-series, or ii) not reporting quantitative details of the SF-36 questionnaire.
Quality assessment
The methodological quality of the studies was evaluated using the “A Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions” (ACROBAT-NRSI) [18].
Data extraction
Two authors (MB and NLB) extracted the data from the studies, and if there was a controversy between them, another author (AA) resolved the issue. The name of first authors of the studies, the year of publication, the place where the studies were conducted, the number of participants, the duration of diabetes, the design, and the mean scores of SF-36 domains were extracted.
Statistical analysis
The pooled value of the mean of overall scores, as well the scores of the eight domains of the questionnaire and the PCS and MCS scores were calculated as the mean and SE. Random-effect model was used and the means were reported with their 95% confidence interval (CI). To evaluate the heterogeneity among studies, I2 test was used [19]. For evaluating the potential sources of heterogeneity, subgroup analyses based on the study design, sample size and type of diabetes (type 1 and type 2 diabetes) were conducted. Sensitivity analysis was performed to ensure that the results were stable. This analysis was also performed based on the year of publication. Egger’s regression test was used to assess the publication bias [20].
Finally, case-control studies were pooled together, computing the standardized mean difference (SMD).
Figures with a p-value < 0.05 were considered statistically significant. All data were analyzed using Stata 12.0 software (Stata Corp LP, College Station, TX).
Results
After the initial electronic database search, 378 studies were found. Eighty-three duplicate studies were deleted. The titles of the retrieved studies were reviewed and 258 studies were excluded due to lack of relevance to the topic. Then, the title and abstract of 37 remaining studies were reviewed by two authors independently and 21 studies were excluded with reason. Finally, the full texts of the remaining 16 studies were examined and, based on the inclusion/exclusion criteria, 14 studies were retained in the final analysis [21‐34]. Figure 1 summarizes the stages of the retrieval and selection of the studies.
×
The included studies were conducted between 2011 and 2017. The total number of participants in the studies was 4492, ranging from 60 to 1847 people. The study designs varied across studies and were cross-sectional for 10 studies and case-control for 4 studies). Table 1 shows the main characteristics of the studies retained in the present systematic review and meta-analysis.
Table 1
The main characteristics of the included studies about general health status in Iranian patients with diabetes
First author
Year of publication
Mean score of general health status
Sample size
Female
Male
Age (Mean ± SD)
Type of diabetes
Design of study
Duration of diabetes (Year ± SD)
Married (%)
Setting (City)
Setting (Province)
Borzou
2011
55.53
165
111
54
NA
Type 2
Cross- Sectional
NA
NA
Hamedan
Hamedan
Khaledi
2011
45.23
198
166
32
NA
Type 2
Cross- Sectional
1–5
80.8
Sannadaj
Kurdistan
Saadatjoo
2012
28.52
100
54
46
42.82 ± 16.57
Type 2
Case-Control
NA
82
Birjand
South Khorasan
Timareh
2012
52.97
350
204
146
52.91 ± 11.7
Both type
Cross- Sectional
NA
86.9
Kermanshah
Kermanshah
Sadabadi
2013
44.72
60
NA
NA
NA
Type 2
Case-Control
NA
NA
Tabriz
East Azerbaijan
Darvishpoor Kakhki
2013
46.2
131
79
52
NA
Type 2
Case-Control
NA
80.2
Tehran
Tehran
Hadi
2013
54.11
300
222
78
50.98
Both type
Cross- Sectional
NA
84
Shiraz
Fars
Darvishpoor Kakhki
2013
52.11
140
NA
NA
47.3 ± 12.7
Both type
Cross- Sectional
8.83 ± 6.10
NA
Tehran
Tehran
Mohammadshahi
2015
51.81
110
51
59
53.4 ± 8.12
Type 2
Cross- Sectional
NA
NA
Ahvaz
Khuzestan
Kashfi
2015
61.33
124
89
35
59.65 ± 12.3
Type 2
Case-Control
7.68 ± 6.93
83.9
Larestan
Fars
Borhaninejad
2016
46.48
120
69
51
71.32 ± 5.13
Type 2
Cross- Sectional
NA
73.4
Kerman
Kerman
Hajian-Tailaki
2016
56.27
747
372
375
68 ± 7.6 in male and 67.7 ± 7.9 in female
Type 2
Cross- Sectional
NA
NA
Babol
Mazandaran
Mazloomy Mahmood Abad
2017
59.27
100
59
41
51.92 ± 11.53
Type 2
Cross- Sectional
NA
94
Sirjan
Kerman
Gholami
2017
51.11
1847
1289
558
59.65 ± 12.3
Type 2
Cross- Sectional
NA
19.9
Nishabur
Razavi Khorasan
The quality assessment of the risk of bias of the included studies is shown in Table 2 and Fig. 2.
Table 2
Risk of Bias Assessment of included studies based on the ACROBAT-NRSI instrument
Study
Domains of bias
Bias due to confounding
Bias in selection of participants
Bias in measurement of interventions
Bias due to departures from intended interventions
Bias due to missing data
Bias in measurement of outcomes
Bias in selection of reported results
Borzou
Moderate risk
Low risk
Low risk
Low risk
Low risk
Low risk
Low risk
Khaledi
Low risk
Low risk
Low risk
Moderate risk
Low risk
Low risk
Moderate risk
Saadatjoo
Serious risk
Low risk
Serious risk
Moderate risk
Serious risk
Moderate risk
Serious risk
Timareh
Serious risk
Moderate risk
Low risk
Moderate risk
Moderate risk
Low risk
Moderate risk
Sadabadi
Moderate risk
Low risk
Moderate risk
Serious risk
Moderate risk
Moderate risk
Low risk
Darvishpoor Kakhki
Serious risk
Low risk
Low risk
Moderate risk
Low risk
Moderate risk
Low risk
Hadi
Low risk
Low risk
Moderate risk
Low risk
Low risk
Low risk
Low risk
Darvishpoor Kakhki
Moderate risk
Low risk
Low risk
Low risk
Low risk
Moderate risk
Low risk
Mohammadshahi
Low risk
Moderate risk
Low risk
Low risk
Low risk
Moderate risk
Low risk
Kashfi
Low risk
Low risk
Low risk
Low risk
Low risk
Low risk
Moderate risk
Borhaninejad
Moderate risk
Low risk
Moderate risk
Moderate risk
Low risk
Low risk
Low risk
Hajian-Tailaki
Low risk
Low risk
Low risk
Moderate risk
Moderate risk
Low risk
Low risk
Mazloomy Mahmood Abad
Low risk
Moderate risk
Low risk
Low risk
Low risk
Low risk
Low risk
Gholami
Moderate risk
Low risk
Low risk
Moderate risk
Low risk
Low risk
Low risk
×
The mean general health status using SF-36 based on the random-effect model in diabetic patients of Iran was 51.9 (95% CI: 48.64 to 53.54). The lowest health status was observed in the study of Saadatjoo with a score of 28.52 and the highest in Kashifi’s study, with a value of 61.33. Figure 3 shows the overall general health status among the included studies.
×
Using the Egger’s test, no publication bias could be detected (p = 0.859, see Fig. 4).
×
To investigate the possible sources of heterogeneity between studies, subgroup analysis was conducted based on study design, sample size and study quality. Table 3 shows the results of subgroup analysis.
Table 3
The results of subgroup analysis
Variables
Number of studies
Number of participants
Mean score of general health status (95% CI)
I2
P-value
Design of studies
Cross-sectional
10
4077
52.32 (50.02–54.62)
86.8%
0.001
Case-control
4
415
46.47 (38.87–54.08)
93.3%
0.001
Sample size
≤120
6
614
49.58 (43.11–56.05)
92%
0.001
> 120
8
3878
51.60 (48.95–54.24)
90.7%
0.001
Type of diabetes
Type 2
11
3702
50.46 (47.43–53.49)
92.46%
0.001
Both type (type 1 and 2)
3
790
53.22 (51.37–55.07)
0%
0.001
For further evaluation of sources of heterogeneity, the results of meta-regression were analyzed based on the year of publication and the sample size of studies, as presented in Table 4. The results showed that the quality of life of diabetic patients has increased on a yearly basis and has decreased based on the sample size. However, none of the results were statistically significant.
Table 4
The results of meta-regression
Variables
Coefficient
S.E.
t
P-value
Lower 95%
Upper 95%
Year
1.36
1.07
1.27
0.22
−0.99
3.73
Sample size
−0.00
0.00
−0.22
0.82
−0.01
0.00
The results based on the eight domains of the SF-36 questionnaire are presented in Table 5. The mean scores of PCS and MCS are shown in Figs. 5 and 6. The mean of PCS was 52.92 [95% CI: 49.46–56.38], while the mean of MCS was 51.02 [95% CI: 46.87–55.16].
Table 5
The health status based on the 8 domains of the SF-36 questionnaire
Variables
Mean (95% CI)
Heterogeneity
P-value of publication bias
I2
P-value
Physical function
61.62 (55.70–67.53)
98.6%
0.001
0.78
Role physical
49.96 (44.50–55.41)
95.6%
0.001
0.83
Body pain
52.26 (48.47–56.04)
95.8%
0.001
0.57
General health
47.34 (44.15–50.53)
96.5%
0.001
0.01
Vitality
46.99 (43.28–50.69)
97.4%
0.001
0.64
Social function
57.86 (46.87–68.85)
99.7%
0.001
0.15
Role emotional
50.38 (45.29–55.47)
97.4%
0.001
0.28
Mental health
47.79 (40.06–55.52)
99.6%
0.001
0.32
×
×
Anzeige
Finally, case-control studies were pooled together (Fig. 7). The general health status of diabetic patients compared to healthy controls was lower with a SMD of − 0.84 [95% CI: -1.83 to 0.51] and compared to the group of patients with tuberculosis with a SMD of 0.44 [95% CI: 0.21- 0.67].
×
Discussion
In the 14 studies included in this systematic review and meta-analysis, numerous complications and co-morbidities were reported in people with diabetes. Health policy- and decision-makers should pay attention to the implications of the reduced general health status in diabetic patients in Iran. Various studies have, indeed, shown that health status is an independent prognostic predictor of survival and hospitalization rate in patients with peripheral arterial and renal patients, and of mortality in patients with coronary heart disease [35‐38].
General health status is decreased in diabetic patients [39], when compared to the health status of general population, which, in a recent study, reported an average score of 67.69 ± 14.78 [40]. Healthcare providers should be aware of the patients’ perspective and their perceived health. Preventing further diabetes complications and providing better conditions for patients’ lives is fundamental. Physical and mental interventions can improve the health status of diabetic patients and avoid, or at least delay, further deterioration [41].
Our findings showed that the dimensions of physical and social function had the highest score whereas the lowest score was related to vitality and general health. The results of our study are consistent with the study done in Brazil [42], whereas other studies reported higher values [43‐45]. The level of access to health services, the economic and social conditions of people, the physical and mental conditions of individuals can, at least partially, explain these differences [46, 47]. Some studies point to the existence of health inequalities in that people with a higher socioeconomic status have more incentive and energy to change their livelihood and are more involved in their own health care processes [48]. An important cross-sectional survey of 13 national samples from Asia, Australia, Europe and North America of 5104 patients with diabetes from the multinational study of Diabetes Attitudes, Wishes and Needs (DAWN) has shown that the reported levels of well-being, self-management, and diabetes control correlate with country, respondent demographic and disease characteristics, as well as with healthcare features [49]. These findings have been replicated by a follow-up study [50].
Anzeige
The findings of the present study indicate that diabetes dramatically affects vitality and general health domains; hence these areas should be given more attention when treating diabetic patients. In our study, MCS was less than PCS, which was consistent with the results of the Al-Shehri study [51]. Various studies have been conducted to show that mental disorders such as depression in patients with diabetes can be remarkably observed. In a review, results showed that depression in diabetic patients had a negative effect on the treatment process and increased complications of the disease [52].
It seems that the chronic and severe nature of diabetes mellitus in the long run leads to a decrease in the general health status [53]. It should be noted that the core of the concept of reported/perceived health status is a feeling/perception of one’s own health and, in fact, other aspects of the health status form a sense of health that is low in patients with diabetes. Affecting the emotional aspects impacts on energy and vitality of patients with diabetes. Other studies have also shown a decrease in vitality, with an increase of fatigue, depression, anxiety and stress problems, among patients with diabetes. Therefore, diabetes has a long-term negative effect on the health of patients. The decrease in the health status in patients with diabetes has also been replicated in other studies [54].
These observations can be confirmed if we compare health status of Iranian subjects with diabetes with the health status of people with chronic-degenerative disorders, such as rheumatoid arthritis with an average score of 52.47 [55], or cardiovascular disorders with a mean of 53.19 [56], among others. Similarly, low scores have been found for asthma [57] or chronic kidney disease [58]. Scores even lower (40.43 ± 12.7) were reported for individuals with drug addiction [59].
In meta-analysis studies, taking into account potential sources of heterogeneity is crucial [60]. To investigate this aspect, we performed subgroup-analysis based on each SF-36 scale domain. The results of meta-regression were also studied for further evaluation of heterogeneity sources, which showed an increased average health status of diabetic patients based on the year of publication, even though not statistically significant. In recent years the status of services provided to diabetics is on the rise, but it seems that many of the services provided to them are not of sufficient standards, and the quality of care for these patients should be monitored more closely by healthcare providers in Iran.
Anzeige
However, this study has some limitations that should be properly mentioned. First, the primary studies missed to give some complementary information about patients, such as sex, other illnesses/co-morbidities, education level and income. Second, a high level of heterogeneity was observed, which can be attributed to methodological differences. Third, the health status in diabetic patients has not been studied in many Iranian provinces, which can challenge the generalizability of our estimation to all Iranian diabetic population.
Conclusion
The findings of this study showed that general health status in Iranian diabetic patients is low. Health policy- and decision-makers should work to improve the health status in these patients and take appropriate interventions. Therefore, it is recommended to look at important factors such as patients’ attitudes in changing and improving their lifestyle. A combination of both clinical and non-clinical interventions should be targeted at increasing the standard of living of these patients.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Availability of data and materials
Not applicable. This study is a systematic review and we used primary data, which are already publicly available.
Ethics approval and consent to participate
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.