Factors affecting the quality of life in women with gestational diabetes mellitus: a path analysis model

This cross-sectional study was conducted on 329 women with GD referred to health care centers in Qom during 2018. First, all health clinics in Qom were identified. Then, we referred to the clinic, and obtained a list of patients, and then the patients with GD were identified. Then, by convenience sampling method, the subjects were selected to complete the sample size. In order to determine the sample size, the following formula was considered with the prevalence of 18% GD based on previous study in Iran [27], 95% confidence interval and precision (d) of 4%.

The incomplete questionnaires were excluded from the study (7% of the questionnaires) and finally 329 questionnaires were analyzed.

The study inclusion criteria were as follows: women who were diagnosed with GD according to the country’s guide, and received pregnancy care services from one of the health care centers in Qom city.

To reach the people, telephone coordination was used and before the research tool was provided, the goals of the study and the willingness of people to participate in the study were evaluated, the written informed consent from the study participants was obtained, and the questionnaire was provided with the necessary explanations. The participants were asked to answer all the questions with accuracy. If participants had any doubts concerning how to fill each part, they were asked to contact the researcher. Some mothers tended to take the questionnaire home and fill it, which allowed them to fill in each questionnaire for about 60 min. The ethics committee of Alborz University of Medical Sciences approved the study (Ethical Code: Abzums.​ac.​ir.1306.91.)

Several questionnaires were used to collect data.

2. Knowledge: A questionnaire containing 13 items was used that included 6 items regarding gestational diabetes and its risk factors, 4 items about screening and treatment, and 3 questions about the outcome of the disease in pregnancy that were answered by yes or no. This questionnaire was taken from the Elmurugan & Arounassalame study [28], based on the classification of main designers of the questionnaire; 0–4 scores, indicating low knowledge, 5–8 representing medium, and above 9 representing appropriate knowledge. Validity and internal consistency of this questionnaire was evaluated by content validity and Kuder - Richardson respectively. The Kuder Richardson value was 0.75.

3. Attitudes: The attitude questionnaire consisted of 12 items designed according to Anderson et al. [29] questionnaire. The attitude of women with gestational diabetes was assessed about receiving education for diabetes care, seriousness of the disease and glucose control importance. Higher scores represent a more positive attitude. The questionnaire is based on a five- point Likert scale ranging from 1 “completely disagree” to 5 “completely agree”. The content validity was used for the questionnaire validity and Cronbach’s alpha coefficient for internal consistency (it was equal 0.82).

4. SE: To assess SE, the Paradly et al. [30] questionnaire was used. According this tool, the participants were asked to list their confidence to achieve certain behaviors related to diabetes control. This questionnaire consisted 35 items was scored based on a five- point likert scale (1. very sure, I cannot do it; 2. Somewhat sure, I cannot do it; 3.not sure, if I can do it; 4. Somewhat sure, I can do it and 5. Very sure, I can do it). In order to calculate the score of SE, the items score was accumulated. Higher scores represent a more SE. The content validity was used for the questionnaire validity and Cronbach’s alpha coefficient for internal consistency (it was equal 0.77).

5. SS: The SS questionnaire was used in diabetic individuals for SM. This questionnaire was designed by Naderi Magham et al. [31] and contained 30 questions that were scored based on a five- point likert scale from always (5) to never (1). This instrument includes nutritional subscales (9 questions), physical activity (5 questions), blood glucose monitoring (7 questions), foot care (6 questions) and smoking (3 questions). To calculate the scores at first we scored all items from 1 to 5, second to calculate the row score for each subscale, we added item raw scores and then divide it to number of items in that subscale, third, to transfer row scores to a score ranging from 0 to 100, we used the following formula to calculate the final score: The subscale score = [(subscale row score–1)/4] × 100 [31]. This questionnaire was validated in Iran [31]

6. Pregnancy Distress: In this study, pregnancy distress was measured by Tilburg pregnancy distress questionnaire developed by Pop et al. [32] in 2011 and consisted of 16 items and two subscales. The first one is “Negative Affect” and the second is “Social (partner engagement). the first subscale includes 12 items and second subscale includes 4 items. The instrument items were scored based on a 4 -point Likert scale (0. Often, 1: quite often, 2: sometimes, and 3: rarely or never) the scores of 3rd, 5th 6th, 7th, 9th 10th, 11th, 12th, 13th, 14th and 16th items were inversed. The minimum and maximum score is 0 and 48 respectively. The content validity was used for the questionnaire validity and Cranach’s alpha coefficient for internal consistency (it was equal 0.75).

7. SM: SM questionnaire was developed by Schmitt et al. (2013) [33] in 2013. The questionnaire contains 16 questions, which are based on a 4-point Likert scale from 0 (does not apply to me) to 3 (very much apply to me). It includes different areas of SM includes glucose control, physical activity, nutrition, taking the services, and a question that evaluates SM in general. In order to calculate the score of each field, first, its scores were accumulated, then the sum of scores divided by 15 (all of which except the last one), multiplied by 10, thus the score of each field was calculated. This questionnaire was valid based on expert panel views and reliable based on Cronbach’s alpha coefficient. The Cronbach alpha coefficient was 0.83, 0.79, 0.81, and 0.75 for glucose control, physical activity, nutrition and services respectively.

8. QoL: The World Health Organization Quality of Life questionnaire (WHOQOL-BREF) [34] was used. The questionnaire contained four subscales (such as physical health, mental health, social relationships, and environmental health) and a general score. This instrument was validated by Nejat et al. in Iran [35]..

For content validity a group of experts (10 specialists) evaluated the questionnaires and for determining the reliability, the Cranach’s alpha coefficient was calculated.

All data were analyzed by using SPSS software version 21 and LISRELS software version 8. First, the normality of the variables was evaluated using the Kolmogorov–Smirnov test.

The significance correlation between variables was considered as the first hypothesis of path analysis. Eight factors were identified as factors affecting QoL These factors (knowledge, attitude, SE, SS, Pregnancy distress, SM, age and BMI) were considered as independent variables and QoL was considered as a dependent variable.

In order to evaluate the fitness of the model, the fitting index such as × 2/df, RMSEA (Root mean square error of approximation), CFI (Comparative fit index), GFI (Goodness of fit index), NFI (Normal fit index) and IFI (Incremental fit indices) were computed.

The mean age of participants was 30.93 ± 5.42 years. The majority of participants (73.0%) had a history of disease in their first degree relatives. Most subjects (68.39%) had wanted pregnancy.

49.24% of subjects were controlled their diabetes by diet, 6.99% by drug and %6.99 by insulin injections. The rest of the subjects used a combination regime (e.g., nutrition and drug, nutrition and insulin, drug and insulin) (Table 1).

The correlation between variables is shown in Table 2. A significant correlation was found between the variables and QoL varied from 0.14 to 0.79. The strongest and reverse correlation was found between QoL and BMI (Table 2).

The default relationship between the study variables was based on the evidence presented (Fig. 1). Based on existing literature and the correlation between variables, and according to the model indexes, the default model is tested in Fig. 2. Figure 2 shows the significant relationships of the variables based on the results of t value. In pathways that t-value test is less than 1.96 is not significant and is indicated in red on the figure. But in other pathways that the value of t-test is higher than 1.96, the pathway is significant. Accordingly, the pathways analysis, the indirect ways of SS through SM on QoL SS through distress on QoL, and the indirect path of age through SM on QoL were omitted due to insignificance relationships (t-value less 1.96).

In Fig. 3, the B standard is specified and non-significant pathways are removed. Based on the final model (Fig. 3), only age variable from both direct and indirect paths through BMI had an impact on Qol (B = 0.51). Among variables that directly affected the QoL, supports had the highest effect (B = 1.02) and SE (B = 0.01) had the lowest effect. In the indirect path, only the knowledge variable by affecting the SE had an impact on the QoL (B = 0.0045) (Table 3).

The final path model fitted well (CFI =1, RMSEA = 0.0003, GFI = 0.99), the Goodness of fit Indices for the model indicated in Table 4. The mean and SD of the study variables presented in Table 5. In the present study all variables that entered in the model, were quantitative.