This study is a cross-sectional investigation, and information was gathered primarily through self-administered questionnaires, including basic socio-demographic and clinical data, self-reported HRQL, and self-perceptions of aging. Socio-demographic and clinical data included age, gender, marital status, educational attainments, living arrangements, status of BP control, duration of hypertension, the number of comorbidities and body mass index (BMI), which were covariates of HRQL and must be controlled when analyzing the association between self-perceptions of aging and HRQL [
20]. After obtaining signed informed consent forms, investigators invited patients to complete the investigation. Nurse and student investigators were trained in questionnaire administration before the start of the survey, including data collection and verification methods, and how to communicate accurately and effectively with participants. For illiterate participants, investigator researchers read the question items word-by-word, exactly as printed on the questionnaire. At the end of the investigation, each participant had his or her BMI measured. This study was approved by the ethics committee of Changshu No.1 People’s Hospital.
Study population
This cross-sectional survey was carried out in 15 urban community clinics and 22 rural village clinics in Suzhou, China. Because the population density of Suzhou municipality is less than 1500 people per square kilometer, we defined the areas where the sub-district offices were located and the constructed towns as urban, and the other areas where more than 50% residential population were farmers as rural, according to the demarcation standards of the National Bureau of Statistics and the State Council of China. There were approximately 3, 800 inhabitants in each urban community and 4, 800 inhabitants in each rural village. Participants aged 60 years or above who sought medical advice in study clinics were recruited between November 2013 and December 2016. Subjects who reported ever having been diagnosed with hypertension by a qualified health care provider and were able to communicate were invited to participate in this study. Hypertension was defined as systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥ 90 mmHg or the use of antihypertensive medications [
21]. Each potential subject was verbally asked about the history of their diseases and medications and verified by their medical records to confirm study eligibility. Subjects were excluded if they had any of the following conditions that would prohibit participation or have a great impact on HRQL: dementia or cognitive impairment, cancer, heart failure (New York Heart Association functional class III or IV), or unstable angina.
We used G*Power version 3.1 software to estimate the sample size. With a medium effect size at 0.10 and a power of 0.90, the sample size for 16 predictors to achieve α at 0.01 was 331. Considering that there might be 30% of questionnaires having missing or implausible information, the total sample size of urban and rural hypertensive patients should not be less than 860.
Instrument
The participants’ age, gender, marital status, educational attainments, living arrangements, status of BP control, duration of hypertension, and the number of comorbidities were gathered through a self-reported survey by trained researchers. Hypertensive clients with BP < 140/90 mmHg in their last appointment were considered to have their BP controlled. The height and weight were measured using a calibrated stadiometer and weight scale for patients wearing light clothing without shoes. The BMI was calculated as the weight (in kilograms) divided by the square of the height (in metres).
HRQL was measured using the short form-36 (SF-36), which has been used in different populations [
22‐
24]. SF-36 is a self-administered questionnaire that generates assessment scores across 36 scales. These scales are scored on a 0–100 scale, with higher scores indicating better HRQL. The following 8 dimensions of HRQL are evaluated by these scores: physical functioning (PF), role limitations due to physical problems (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social functioning (SF), role limitations due to emotional problems (RE), and mental health (MH). The SF-36 dimensions can be reduced to 2 aggregate summaries with the first four dimensions indicating respondents’ physical component summary (PCS) and the last four indicating mental component summary (MCS) [
25]. The mandarin version of the SF-36 used in this study has been administered successfully in general populations in China with the internal reliability coefficients of the PCS and MCS scales ranging from 0.85 to 0.87 [
26,
27] and its validity and reliability have been tested in Chinese hypertensive clients [
28]. The PCS and MCS scores were calculated based on the Chinese population norm [
27].
Self-reported perceptions of aging were measured using the 32-item aging perceptions questionnaire (APQ) developed by Barker et al. in 2007 [
29]. The 32 items comprised 7 subscales examining aging views: timeline chronic, timeline cyclical, consequences positive, consequences negative, control positive, control negative, and emotional representations. “Timeline chronic” relates to the awareness of the chronic nature of aging (e.g., ‘I always classify myself as old’), and “timeline cyclical” reflects the variation in the awareness of aging (e.g., ‘I go through phases of feeling old’). “Consequences” refers to beliefs about the impact of aging on one’s life, including positive consequences (e.g., ‘As I get older, I get wiser’) and negative consequences (e.g., ‘Getting older makes everything harder for me’). “Control” refers to elders’ beliefs about managing one’s experience of aging, which can be positive (e.g., ‘The quality of my social life in later years depends on me’) or negative (e.g., ‘Immobility in later life is not up to me’). “Emotional representations” demonstrate the negative emotions generated by aging (e.g. ‘I get depressed when I think about getting older’). Answers are provided on a 5-point scale, ranging from 1 ‘strongly disagree’ to 5 ‘strongly agree’. The response scale of the control negative dimension is reversed (1 ‘strongly agree’ to 5 ‘strongly disagree’). The mean score for each subscale is calculated with higher scores indicating greater endorsement of a specific perception. A Chinese version of the APQ was used, with Cronbach alpha coefficients of 0.884 for the total scale, 0.869 for timeline chronic, 0.700 for timeline cyclical, 0.665 for consequences positive, 0.836 for consequences negative, 0.822 for control positive, 0.748 for control negative, 0.835 for emotional representations, and cumulative variance contribution rate 65.269% [
30].
Analytical strategy
All data were analyzed using SPSS 20.0 (SPSS, Chicago, Illinois, USA). All continuous variables were expressed as mean ± standard deviation (SD), and the categorical variables were summarized by frequencies or percentage. Socio-demographic and clinical characteristics were calculated for rural and urban participants, and the significance of differences across groupings were determined using the Chi-square test for nominal variables and Student’s
t-test for independent samples for continuous variables (Table
1). Multivariate analysis of variance (MANOVA) was used to control demographic characteristics and compare the differences of HRQL and self-perceptions of aging between urban and rural participants (Tables
2 and
3). Multivariate linear regression was utilized to assess the association between self-perceptions of aging and PCS and MCS adjusted for age (numerical), gender, marital status (single or divorced or widowed vs. married), educational attainments (junior middle school and below vs. senior high school and above), living arrangements (with family vs. alone), BMI (numerical), duration of hypertension (numerical), and comorbidities (with vs. without) (Tables
4 and
5). The coefficient and 95% confidence interval (95% CI) are presented. All statistical tests were two-sided and tests of alpha less than 0.05 were considered statistically significant.
Table 1
Socio-demographic and Clinical Characteristics for Urban and Rural Participants
Gender, n (%) | 4.890 | 0.027 |
Male | 263 (53.5%) | 250 (46.6%) | | |
Female | 229 (46.5%) | 287 (53.4%) | | |
Age (years), Mean ± SD | 68.4 ± 7.5 | 70.8 ± 9.2 | −4.569 | < 0.001 |
Marital status, n (%) | 4.968 | 0.026 |
Single/divorced/widowed | 91 (18.5%) | 130 (24.2%) | | |
Married | 401 (81.5%) | 407 (75.8%) | | |
Educational attainments, n (%) | 196.371 | < 0.001 |
Junior middle school and below | 316 (64.2%) | 526 (98.0%) | | |
Senior high school and above | 176 (35.8%) | 11 (2.0%) | | |
Living arrangements, n (%) | 3.342 | 0.068 |
Alone | 44 (8.9%) | 32 (6.0%) | | |
With family | 448 (91.1%) | 505 (94.0%) | | |
BMI (kg/m2), M ± SD | 23.6 ± 3.2 | 24.0 ± 4.0 | −1.845 | 0.065 |
Blood pressure control, n (%) | 158.759 | < 0.001 |
Yes | 366 (74.4%) | 189 (35.2%) | | |
No | 126 (25.6%) | 348 (64.8%) | | |
Hypertension duration (years), Mean ± SD | 9.1 ± 8.3 | 10.8 ± 7.2 | −3.480 | 0.001 |
Comorbidities, n (%) | 0.173 | 0.677 |
No | 263 (53.5%) | 294 (54.7%) | | |
Yes | 229 (46.5%) | 243 (45.3%) | | |
Table 2
SF-36 Scores for Urban and Rural Participants
Physical functioning | 73.9 ± 22.5 | 70.5 ± 23.9 | 15.384 | < 0.001 |
Role physical | 65.2 ± 38.0 | 80.2 ± 36.7 | 10.808 | 0.001 |
Bodily pain | 76.6 ± 20.5 | 9.1 ± 13.0 | 1.017E3 | < 0.001 |
General health | 44.1 ± 16.3 | 45.8 ± 6.2 | 0.618 | 0.432 |
Vitality | 67.8 ± 16.5 | 59.6 ± 14.8 | 112.239 | < 0.001 |
Social functioning | 85.4 ± 16.4 | 45.7 ± 20.3 | 285.632 | < 0.001 |
Role emotional | 69.7 ± 37.2 | 85.4 ± 31.8 | 10.231 | 0.001 |
Mental health | 65.6 ± 15.8 | 57.9 ± 14.8 | 50.085 | < 0.001 |
PCS | 40.0 ± 12.1 | 30.9 ± 8.9 | 144.300 | < 0.001 |
MCS | 51.5 ± 8.3 | 46.0 ± 7.8 | 136.752 | < 0.001 |
Table 3
Scores on Each Domain of Self-perceptions of Aging for Urban and Rural Participants
Timeline chronic | 3.0 ± 0.9 | 3.1 ± 0.8 | 0.017 | 0.897 |
Timeline cyclical | 3.3 ± 0.7 | 3.6 ± 0.6 | 32.923 | < 0.001 |
Consequences positive | 3.5 ± 0.7 | 3.3 ± 0.7 | 17.493 | < 0.001 |
Consequences negative | 3.1 ± 0.8 | 3.6 ± 0.6 | 114.586 | < 0.001 |
Control positive | 3.6 ± 0.7 | 3.3 ± 0.6 | 45.438 | < 0.001 |
Control negative | 3.0 ± 0.7 | 3.4 ± 0.6 | 19.993 | < 0.001 |
Emotional representations | 2.7 ± 0.8 | 2.6 ± 0.6 | 0.428 | 0.513 |
Table 4
Association between Self-perceptions of Aging and PCS for Urban and Rural Participants
Self-perceptions of aging |
Timeline chronic | −1.17 | −2.28, − 0.06 | 0.038 | −3.21 | −4.24, − 2.18 | < 0.001 |
Timeline cyclical | − 0.01 | − 1.66, 1.64 | 0.988 | − 1.91 | − 3.64, − 0.18 | 0.031 |
Consequences positive | − 0.19 | −1.54, 1.16 | 0.779 | 1.15 | 0.07, 2.24 | 0.037 |
Consequences negative | −2.07 | −3.43, − 0.71 | 0.003 | 1.57 | − 0.21, 3.35 | 0.084 |
Control positive | 2.08 | 0.70, 3.45 | 0.003 | 0.34 | −0.92, 1.60 | 0.596 |
Control negative | 0.26 | −1.20, 1.72 | 0.724 | − 1.45 | −3.03, 0.13 | 0.073 |
Emotional representations | −1.50 | −2.97, −0.03 | 0.045 | −4.31 | −5.56, −3.05 | < 0.001 |
Controlled variables |
Gender (ref: male) | −2.36 | −4.22, −0.49 | 0.013 | − 1.81 | −3.16, − 0.46 | 0.009 |
Age | −0.20 | − 0.35, − 0.06 | 0.006 | −0.07 | − 0.17, 0.03 | 0.152 |
Marital status (ref: single/divorced/widowed) | 2.61 | −0.17, 5.38 | 0.065 | 0.43 | −1.35, 2.22 | 0.663 |
Educational attainments (ref: junior middle school and below) | −0.53 | −2.49, 1.43 | 0.598 | −4.43 | −9.16, 0.29 | 0.066 |
Living arrangements (ref: alone) | −2.15 | −5.78, 1.48 | 0.246 | −1.84 | −4.89, 1.21 | 0.236 |
BMI | −0.04 | −0.32, 0.24 | 0.789 | 0.10 | −0.07, 0.27 | 0.254 |
Blood pressure control (ref: no) | 0.68 | −1.38, 2.73 | 0.519 | 0.16 | −1.26, 1.56 | 0.830 |
Hypertension duration | −0.10 | −0.22, 0.02 | 0.111 | −0.09 | −0.20, 0.01 | 0.069 |
Comorbidities (ref: no) | −7.34 | −9.35, −5.33 | < 0.001 | −0.15 | −1.60, 1.29 | 0.834 |
Table 5
Association between Self-perceptions of Aging and MCS for Urban and Rural Participants
Self-perceptions of aging |
Timeline chronic | 0.11 | −0.75,0.97 | 0.801 | −2.52 | −3.47, −1.56 | < 0.001 |
Timeline cyclical | −0.86 | −2.14, 0.43 | 0.191 | 0.17 | −1.45, 1.78 | 0.841 |
Consequences positive | 0.45 | −0.60, 1.50 | 0.399 | −0.25 | −1.25, 0.76 | 0.632 |
Consequences negative | −0.04 | −1.10, 1.01 | 0.935 | −1.13 | −2.79, 0.52 | 0.179 |
Control positive | 1.89 | 0.82, 2.96 | 0.001 | 0.62 | −0.55, 1.78 | 0.302 |
Control negative | 0.94 | −0.20, 2.07 | 0.106 | 1.43 | −0.04, 2.91 | 0.057 |
Emotional representations | −2.41 | −3.55, −1.26 | < 0.001 | −1.72 | −2.88, −0.55 | 0.004 |
Controlled variables |
Gender (ref: male) | 1.32 | −0.13, 2.77 | 0.074 | 1.57 | 0.31, 2.83 | 0.015 |
Age | 0.20 | 0.09, 0.31 | 0.001 | −0.02 | −0.12, 0.07 | 0.632 |
Marital status (ref: single/divorced/widowed) | −0.42 | −2.58, 1.73 | 0.701 | −1.64 | −3.30, 0.02 | 0.053 |
Educational attainments (ref: junior middle school and below) | 0.49 | −1.03, 2.02 | 0.526 | −1.11 | −5.51, 3.28 | 0.620 |
Living arrangements (ref: alone) | 1.19 | −1.63, 4.02 | 0.407 | 1.18 | −1.66, 4.01 | 0.416 |
BMI | 0.18 | −0.04, 0.40 | 0.101 | −0.10 | − 0.26, 0.06 | 0.210 |
Blood pressure control (ref: no) | 0.26 | −1.34, 1.86 | 0.752 | −0.22 | −1.54, 1.09 | 0.738 |
Hypertension duration | 0.04 | −0.06, 0.13 | 0.435 | 0.05 | −0.05, 0.14 | 0.331 |
Comorbidities (ref: no) | −2.65 | −4.22, −1.09 | 0.001 | 0.51 | −0.84, 1.85 | 0.458 |