Questionnaire development
A total of 2152 documents were obtained, and 763 documents were selected, including 345 in Chinese and 418 in English. The entry pool consists of 46 entries. Following group discussions and expert consultations, a thorough review resulted in manual removal of 18 duplicate and similar items. Consequently, an initial Out-of-Hospital Adherence Questionnaire consisting of 28 items was developed. This questionnaire included 8 items related to medication adherence(A), 5 items related to self-monitoring adherence(B), 8 items related to rehabilitation adherence(C), and 7 items related to adherence to lifestyle behavior changes(D). Each question was formatted as a single-choice one (Fig. 2).
Expert consultation and content validity
A total of 15 experts in related fields were consulted in the first round, including experts in health communication, behavioral science, public health policy, health promotion, stroke disease prevention and control, health career management, basic medical education research, and nutrition and health. The average number of years was 24.2 ± 6.89 (Table 1).
Table 1 Characteristics of the experts(n=15)
Characteristic
|
No. of experts
|
Proportion(%)
|
Gender
|
|
|
Male
|
2
|
13.33
|
Female
|
13
|
86.67
|
Age
|
|
|
26~30
|
1
|
6.67
|
31~40
|
2
|
13.33
|
41~50
|
9
|
60
|
51~60
|
3
|
20
|
Education
|
|
|
Bachelor’s degree and blow
|
10
|
66.67
|
Master’s degree
|
1
|
6.67
|
Doctorate degree
|
4
|
26.67
|
Professional title
|
|
|
Senior
|
3
|
20
|
Vice-senior
|
5
|
33.33
|
Middle
|
7
|
46.67
|
Primary
|
0
|
|
The Ca values in the two rounds of correspondence in this study were 0.85 and 0.87, respectively. The experts' familiarity with the Cs values were 0.88 and 0.89, respectively. The experts' Cr values were 0.87 and 0.88, respectively. All 15 experts were found to have high Cr values based on their self-identification. The Ca value ranged from 0.7 to 1.0, while the Cs value ranged from 0.8 1.0. The level of expert authority was deemed high.
KW values were calculated for each factor, yielding KW(A) = 0.344, KW(B) = 0.525, KW(C) = 0.299, and KW(D) = 0.282. The results were statistically significant (P < 0.01), indicating a high level of agreement among experts. The level of consensus among the expert viewpoints was deemed satisfactory, as all the scores were less than 0.25. Furthermore, the questionnaire underwent a second round of modifications in which expert viewpoints were incorporated to make the necessary deletions.
The second round of the expert consultation form involved 27 items across four dimensions. The KW values for each dimension were as follows: KW(A) = 0.533, KW(B) = 0.573, KW(C) = 0.575, and KW(D) = 0.672 (P < 0.05). One entry from the life behavior change adherence dimension that did not match the criteria was ultimately removed, resulting in 26 entries in the preliminary questionnaire (Table 2).
Table 2
The degree of coordination between the two rounds of expert opinions
Round | Dimensions | Items | Number of experts | CV | KW | | P |
Round 1 | Medication Adherence | 8 | 15 | 0.072 | 0.344 | 36.165 | <0.001 |
Self-monitoring Adherence | 5 | 15 | 0.079 | 0.525 | 31.489 | <0.001 |
Rehabilitation Adherence | 8 | 15 | 0.051 | 0.299 | 31.355 | <0.001 |
Life behaviors change Adherence | 7 | 15 | 0.096 | 0.282 | 25.346 | <0.001 |
Round 2 | Medication Adherence | 8 | 15 | 0.078 | 0.533 | 48.000 | <0.001 |
Self-monitoring Adherence | 4 | 15 | 0.054 | 0.573 | 34.370 | <0.001 |
Rehabilitation Adherence | 7 | 15 | 0.094 | 0.575 | 51.745 | <0.001 |
Life behaviors change Adherence | 8 | 15 | 0.077 | 0.672 | 70.583 | <0.001 |
Validation of the questionnaire
Questionnaire population validation analysis
To refine the questionnaire, 20 stroke patients who underwent a follow-up assessment in the neurology department of the previously mentioned hospital were randomly chosen for the preliminary survey. The questionnaire has a validity rating of 100%. A total of 12 males and 8 females were included, and the mean age was 61.38 ± 5.83 years. The questions were answered within approximately 7 minutes. The surveys have been revised and modified accordingly. The questionnaire consisted of 26 items distributed across four dimensions, with eight, four, seven, and seven items.
A standardized questionnaire was used to assess patients with stroke who underwent a follow-up assessment in the neurology department of the previously mentioned hospital. A total of 308 participants were included, 290 of whom were considered legitimate. This resulted in a valid recovery rate of 94.16%. A total of 170 males and 120 females participated in this study. The mean age was 59.03 ± 6.11 years. The majority of the patients had literacy levels equivalent to elementary school or junior high school. Married patients constituted 89.66% of the total patient population. Patients’ medical expenses were predominantly reimbursed by China's healthcare insurance (Table 3).
Table 3
General characteristics of stroke patients(n = 290)
Descriptions | No. of respondents | Proportions(%) |
Gender | | |
Male | 170 | 58.62 |
Female | 120 | 41.38 |
Age | | |
<50 | 35 | 12.07 |
51ཞ60 | 83 | 28.62 |
61ཞ69 | 132 | 45.52 |
≥ 70 | 40 | 13.79 |
Education | | |
illiteracy | 16 | 5.52 |
Elementary or middle school | 117 | 40.34 |
senior secondary | 108 | 37.24 |
University or above | 49 | 16.90 |
Matrimonial | | |
married | 260 | 89.66 |
divorcee | 16 | 5.52 |
widowhood | 5 | 1.72 |
unmarried | 9 | 3.10 |
Occupation | | |
incumbency | 37 | 12.76 |
unemployed | 62 | 21.38 |
retired | 124 | 42.76 |
others | 67 | 23.10 |
Residency | | |
countryside | 60 | 20.69 |
towns | 164 | 56.55 |
municipalities | 66 | 22.76 |
Combined chronic diseases | | |
one | 147 | 50.69 |
two | 108 | 37.24 |
three or above | 35 | 12.07 |
First-ever stroke | | |
yes | 124 | 42.76 |
no | 166 | 57.24 |
Type of medical insurance | | |
urban residents | 133 | 45.86 |
New Rural Cooperative Medical Care | 89 | 30.69 |
others | 68 | 23.45 |
Residence | | |
solitary | 101 | 34.83 |
cohabitation | 189 | 65.17 |
(fig.) Repercussions | | |
yes | 95 | 32.76 |
no | 140 | 48.27 |
yes, but recovered | 55 | 18.97 |
Time of first onset | | |
<one month | 94 | 32.41 |
1–6 months | 158 | 54.49 |
> 6months | 38 | 13.10 |
Incomes | | |
<1000 CNY | 44 | 15.17 |
1001–3000 CNY | 78 | 26.89 |
3001–6000 CNY | 69 | 23.80 |
6001–10000 CNY | 53 | 18.28 |
10001–20000 CNY | 32 | 11.03 |
> 20000 CNY | 12 | 4.14 |
don't know. | 2 | 0.69 |
Questionnaire discrimination and homogeneity analysis
The study used a sample of 100 questionnaires from 290 participants. The critical ratio t-test method was employed, employing a grouping criterion of 27% based on the difference in total scores. Two independent-sample t-tests were conducted to determine whether there was a significant difference between the high- and low-risk groups. Typically, the disparity in scores between the two groups is not statistically significant, or the t-value falls below 3, which is the threshold for exclusion. The results indicated that there were no statistically significant differences between the A3, A8, B1, and C5 scores. Consequently, the research team opted to exclude A8 from the dataset while retaining the remaining three entries. All remaining entries had a t value greater than 3, indicating that the questionnaire exhibited a high level of differentiation. All the Pearson correlation coefficients for the total correlation question were above 0.4, suggesting that each item had a high level of internal consistency and that the questionnaire demonstrated good homogeneity31 (Table 4).
Table 4
Analysis of the total correlation of the questions
Item | r | P | Item | r | P |
A-1 | 0.622 | <0.001 | C-3 | 0.488 | <0.001 |
A-2 | 0.585 | <0.001 | C-4 | 0.451 | <0.001 |
A-3 | 0.568 | <0.001 | C-5 | 0.583 | <0.001 |
A-4 | 0.611 | <0.001 | C-6 | 0.457 | <0.001 |
A-5 | 0.580 | <0.001 | C-7 | 0.438 | <0.001 |
A-6 | 0.682 | <0.001 | D-1 | 0.282 | 0.003 |
A-7 | 0.626 | <0.001 | D-2 | 0.275 | 0.004 |
B-1 | 0.512 | <0.001 | D-3 | 0.455 | <0.001 |
B-2 | 0.580 | <0.001 | D-4 | 0.402 | <0.001 |
B-3 | 0.639 | <0.001 | D-5 | 0.34 | <0.001 |
B-4 | 0.569 | <0.001 | D-6 | 0.486 | <0.001 |
C-1 | 0.504 | <0.001 | D-7 | 0.572 | <0.001 |
C-2 | 0.433 | <0.001 | | | |
Questionnaire validity analysis
Exploratory factor analysis of the questionnaire yielded a KMO value of 0.923 and an approximate chi-square value of 8964.138, with a significance level of P < 0.001. These results indicate that the out-of-hospital adherence questionnaire for stroke patients was successful after factor analysis and variable extraction. The questionnaire identified four factors that did not have multivariate loading. The dimensions had high loadings on their respective factors, suggesting that the results of the exploratory factor analysis were consistent with the original design of the scale. This indicates that the questionnaire had good structural validity (Table 5).
Table 5
Analysis of exploratory factor
Dimension | Item | Element |
1 | 2 | 3 | 4 |
Medication Adherence | A-1 | 0.883 | 0.041 | 0.020 | 0.225 |
A-2 | 0.827 | 0.049 | 0.044 | 0.208 |
A-3 | 0.796 | -0.037 | 0.027 | 0.110 |
A-4 | 0.825 | 0.045 | 0.061 | 0.141 |
A-5 | 0.812 | -0.008 | 0.044 | 0.141 |
A-6 | 0.830 | -0.015 | 0.027 | 0.158 |
A-7 | 0.852 | -0.025 | 0.070 | 0.160 |
Self-monitoring Adherence | B-1 | 0.395 | 0.005 | 0.115 | 0.683 |
B-2 | 0.279 | 0.017 | 0.146 | 0.797 |
B-3 | 0.236 | 0.032 | 0.137 | 0.822 |
B-4 | 0.210 | 0.065 | 0.169 | 0.810 |
Rehabilitation Adherence | C-1 | 0.025 | 0.122 | 0.748 | 0.196 |
C-2 | 0.017 | 0.114 | 0.751 | 0.141 |
C-3 | 0.028 | 0.161 | 0.798 | 0.088 |
C-4 | 0.056 | 0.150 | 0.804 | 0.109 |
C-5 | 0.043 | 0.198 | 0.818 | 0.053 |
C-6 | 0.054 | 0.211 | 0.814 | 0.053 |
C-7 | 0.086 | 0.158 | 0.816 | 0.010 |
Life behaviors change Adherence | D-1 | 0.023 | 0.722 | 0.315 | 0.083 |
D-2 | 0.007 | 0.774 | 0.244 | 0.064 |
D-3 | -0.007 | 0.828 | 0.162 | 0.006 |
D-4 | 0.012 | 0.837 | 0.155 | 0.018 |
D-5 | -0.052 | 0.844 | 0.093 | 0.015 |
D-6 | 0.009 | 0.859 | 0.109 | -0.033 |
D-7 | 0.050 | 0.865 | 0.110 | 0.021 |
Furthermore, the results of the factor analysis model validation for the questionnaire indicated that the CMIN/DF value was 2.490, RMR was 0.05, GFI was 0.901, NFI was 0.927, and IFI was 0.955. All of these values met the criteria for an excellent model fit. Additionally, the RMSEA value was less than 0.08, which is considered a good standard for a model fit. These findings suggest that the factor analysis model used in this study is well suited. The questionnaire demonstrated strong aggregate validity, as indicated by standardized loading values ranging from 0.717 to 0.916 across the four dimensions (Table 6 and Fig. 3).
Table 6
Analysis model of adaptation of validating factor
Fit index | CMIN/DF | RMR | GFI | CFI | NFI | IFI | RMSEA |
Standard | <3 | <0.05 | >0.9 | >0.9 | >0.9 | >0.9 | <0.05 excellent <0.08 good |
Results | 2.490 | 0.05 | 0.901 | 0.955 | 0.927 | 0.955 | 0.054 |
Convergent validity measures the degree of agreement between the different aspects of the underlying variable. When examining the four dimensions, the standardized loadings for the measurement items varied from 0.717 to 0.916, all of which were greater than 0.7. The combined reliabilities of the four dimensions were 0.936, 0.864, 0.917, and 0.929, all greater than 0.7. Additionally, the average variance extracted (AVE) values for the four dimensions were 0.676, 0.614, 0.611, and 0.652, all of which exceeded 0.5. Hence, the overall reliability of the questionnaire was satisfactory (Table 7).
Table 7
Analysis of aggregation validity
Item | Non-Standardized Factor loading | Standardized Factor loading | Std. Error | t | Combinatorial reliability | AVE |
Medication Adherence | | | | | | |
A-1 | 1 | 0.916 | | | 0.936 | 0.676 |
A-2 | 0.884 | 0.853 | 0.031 | 28.507*** |
A-3 | 0.802 | 0.746 | 0.037 | 21.810*** |
A-4 | 0.850 | 0.790 | 0.035 | 24.252*** |
A-5 | 0.830 | 0.782 | 0.035 | 23.768*** |
A-6 | 0.863 | 0.811 | 0.034 | 25.587*** |
A-7 | 0.926 | 0.847 | 0.033 | 28.066*** |
Self-monitoring Adherence | | | | | | |
B-1 | 1 | 0.737 | | | 0.864 | 0.614 |
B-2 | 1.062 | 0.815 | 0.061 | 17.365*** |
B-3 | 1.071 | 0.800 | 0.063 | 17.072*** |
B-4 | 1.023 | 0.780 | 0.061 | 16.667*** |
Rehabilitation Adherence | | | | | | |
C-1 | 1 | 0.729 | | | 0.917 | 0.611 |
C-2 | 1.024 | 0.717 | 0.065 | 15.852*** |
C-3 | 1.125 | 0.782 | 0.065 | 17.347*** |
C-4 | 1.155 | 0.795 | 0.065 | 17.644*** |
C-5 | 1.105 | 0.818 | 0.061 | 18.191*** |
C-6 | 1.181 | 0.824 | 0.065 | 18.313*** |
C-7 | 1.124 | 0.801 | 0.063 | 17.790*** |
Life Behavior Change Adherence | | | | | | |
D-1 | 1 | 0.729 | | | 0.929 | 0.652 |
D-2 | 1.046 | 0.767 | 0.061 | 17.170*** |
D-3 | 1.051 | 0.815 | 0.057 | 18.311*** |
D-4 | 1.090 | 0.828 | 0.059 | 18.622*** |
D-5 | 1.118 | 0.811 | 0.061 | 18.212*** |
D-6 | 1.139 | 0.840 | 0.060 | 18.915*** |
D-7 | 1.157 | 0.854 | 0.060 | 19.235*** |
Discriminant validity analysis revealed that the bold numbers represent the square root of the mean variance recovered for each dimension, while the other numbers indicate the correlation coefficients between the different dimensions. The square root of the mean variance extracted for all four dimensions exceeded the correlation coefficient between dimensions. This suggested that there was a distinction between the four dimensions and that the scale demonstrated high discriminant validity (Table 8).
Table 8
Analysis of discriminant validity
Dimensions | Medication Adherence | Self-monitoring Adherence | Rehabilitation Adherence | Life behaviors change Adherence |
Medication Adherence | 0.822 | | | |
Self-monitoring Adherence | 0.563*** | 0.784 | | |
Rehabilitation Adherence | 0.133** | 0.322*** | 0.782 | |
Life behaviors change Adherence | 0.040 | 0.101* | 0.410*** | 0.807 |
*p<0.05;**p<0.01; ***p<0.001; |
Questionnaire reliability analysis
The study revealed that the Cronbach's alpha coefficients for dimensions A, B, C, and D were 0.936, 0.862, 0.916, and 0.928, respectively. Cronbach's alpha coefficient for the total scale was 0.902. Importantly, all Cronbach's alpha coefficients exceeded the threshold of 0.7, indicating a high level of reliability for measuring stroke adherence. The formal questionnaire demonstrated a high internal consistency, reliability, and stability32 (Table 9).
Table 9
Analysis of Cronbach's alpha coefficient for four dimensions
Dimension | Item | Cronbach’s |
Medication Adherence | 7 | 0.936 |
Self-monitoring Adherence | 4 | 0.862 |
Rehabilitation Adherence | 7 | 0.916 |
Life behaviors change Adherence | 7 | 0.928 |
Population (statistics) | 25 | 0.902 |