Table 3.

Summary of studies included in review

Author (year)	Research design	Sample	Location	Measuring medication adherence	Findings	Theme topic
Bi et al (2009)2	A multicentre prospective study	N=2901, average age: 64.5±12, female 948	51 hospitals (41 tertiary and 10 non-tertiary urban hospitals) in China.	Standardised paper case report forms were used to document if participants were adherent to their medication.	Medication adherence was high at the time of hospital discharge, but decreased during follow-up. Patients discharged on more drugs had even lower adherence.	Discharge, lack of follow-up care.
Jin et al (2014)3	Two-group comparison study	N=469, female 142 (30.3%)	Nanjing, Jiangsu Province, China.	Did not use instrument.	Older patients had a significantly decreased medication adherence than younger patients.	Age, income, comorbidity, adverse effects, education, discharge, medication cost/insurance.
Zhang et al (2015)12	Three-group comparison study	N=5926, female 1095 (18%)	Beijing, China.	Participants’ medication adherence was measured by their patterns of beta-blocker use at hospital discharge and during the first year after discharge: (1) always users, (2) never users and (3) inconsistent users.	Consistent beta-blocker use after hospital discharge can lower mortality and cardiovascular events. Among 5926 participants with CHD, 2922 (49.3%) consistently used beta-blocker, whereas 1323 (22.3%) never used it.	Lack of follow-up care.
Jiang et al (2012)13	Cross-sectional study	864 physicians participated in the survey, representing 86% of all attending physicians and residents in cardiology departments in the 35 hospitals.	35 tertiary hospitals located in urban areas of China.	Did not measure medication adherence.	Medication adherence is related to physicians. Knowledge of physicians was not precise or up-to-date.	Lack of follow-up care.
Wang and Li (2014)16	Retrospective analysis study	N=1368, age range: 80–101, average age: 86.4±6.6, female 528	Beijing, China.	Morisky-Green Questionnaire.	Chinese people with CHD older than 80 years had poor adherence to statin. 22% of them did not adhere to their statins.	Age, education, patients’ lack of knowledge, income.
Li (2015)17	Retrospective analysis study	N=138, age range: from 54 to 76, average age: 62.12±10.11, female 68	Enshi City, Hubei Province, China.	Used a self-made scale. Very much like MMAS-4, but one question is different. Validity and reliability were not reported.	Adherence to statins is poor among Chinese people with CHD. 36.23% of them had poor adherence.	Number of discharge medications, adverse effects, income, patients’ lack of knowledge, age, education, medication cost/insurance.
Ding et al (2013)*18	Cross-sectional study	N=903, average age: 64.9±10.7, female 257 (29.3%)	Beijing, China.	Self-made questionnaire.	LDL-C control rate is very low in people with CHD living in Beijing. Only 36.9% reached the standard of LDL-C control.	Patients’ lack of knowledge, lack of follow-up care.
Zhao et al (2015)19	Cross-sectional study	N=159, average age: 61.7 years, female 58 (36.5%)	Zhengzhou, Henan Province, China.	MMAS-8.	Among Chinese people with CHD, those who lack knowledge about their medications were more likely to divert from the instructions for their medication.	Patients’ lack of knowledge.
Dai (2013)*20	Cross-sectional study	N=200, age range: from 28 to 67, female 88	Donggu Village, Pinggu District, Beijing, China.	Used a self-made survey, which was tested in a pilot study.	Medication adherence is poor in Chinese rural areas. 61.7% participants had poor adherence.	Number of discharge medications, adverse effects, patients’ lack of knowledge, education.
Hu et al (2008)21	Cross-sectional study	N=4778, female 1719 (36.0%)	52 medical centres in 6 Chinese cities: Shanghai, Beijing, Guangzhou, Zhejiang, Tianjin and Xinjiang.	Did not use instrument. Adherence to statins was measured as the rate of achieving the target LDL-C level.	18.6% of patients with CHD at high risk of cardiac event were not taking statins as lipid-lowering therapy; 17.5% of patients with CHD at very high risk of cardiac event were not taking statins.	Lack of follow-up care.
Jianget al (2015)*29	Cross-sectional study	N=5407, average age: 67.6, female 2152 (42.9%)	298 hospitals in 15 Chinese provinces.	Did not use instrument. Participants who were adherent were defined as those who were still on their medications at the third month after baseline survey.	Medication non-adherence is common in Chinese people with CHD. Several factors were identified.	Education.
Xu et al (2012)25	A retrospective, cross-sectional study	N=200, female 62	Hangzhou, Zhejiang Province, China.	Medication use was calculated by percentage of participants with CHD who were prescribed cardioprotective medication.	Patients discharged from the Chinese medical hospital were less likely to receive angiotensin receptor blockers/ACEI and beta-blockers than those discharged from the general hospital.	Lack of follow-up care.
Li et al (2016)24	A sequential cross-sectional study	N=2463, female 673	Hospitals were chosen from both economic-geographical regions (eastern, central and western) and rural/urban regions.	Did not use instrument. Used the 2010 Chinese Guideline for Diagnosis and Treatment of Patients with ST-Elevation Myocardial Infarction to determine whether patients received the appropriate fibrinolytic dosage. Appropriate dosage was defined as between 80% and 120% of the recommendation. Underdosing was defined as less than 80% and overdosing was defined as more than 120% of the recommended dose.	Many patients with CHD were not treated with fibrinolytic therapy: only 49.5% ideal candidates for fibrinolytic therapy received it.	Lack of follow-up care.
Wang et al (2015)23	Retrospective analysis study	N=2128, female 724 (34.02%)	20 tertiary hospitals in Heilongjiang Province of China.	Did not use instrument. Medication adherence rate was calculated as the number of eligible patients who actually received the recommended medication divided by all patients eligible for it.	The adherence rates to aspirin, beta-blocker and thrombolytic were much less than the target level recommended by the American College of Cardiology/American Heart Association as first-line treatments for practice guidelines.	Lack of follow-up care.
Li et al (2009)22	Cross-sectional study	N=4778, female 1719	52 centres in 6 cities in China: Shanghai, Beijing, Guangzhou, Xinjiang, Zhejiang and Tianjin.	Did not use instrument.	The number of patients with CHD who achieved the recommended LDL-C level was suboptimal. 18.6% of patients with CHD at high risk did not receive statin therapy; 17.5% at very high risk did not receive statin therapy.	Lack of follow-up care.
Li et al (2012)26	Randomised controlled trial	N=16 860, average age: 63, female 4384 (26%)	72 study sites in 14 Chinese cities.	Did not use instrument. Medication adherence was assessed by the rate of medication usage among participants.	Among Chinese people with CHD, antiplatelet therapy was commonly used, but the use of statins, beta-blockers and ACEIs was still not optimal.	Age, comorbidity, discharge, adverse effects.
Zhuanget al(2016)*27	Cross-sectional study	N=348, age range: from 45 to 75, average age: 60±6, female 166	Shanghai, China.	Did not use instrument. Medication adherence was identified as following physicians’ prescriptions to take antiplatelets. Non-adherence was identified as changing dosage/frequency of prescribed antiplatelets or stopping prescribed antiplatelets.	The percentages of participants who adhered to their antiplatelets were 98.3%, 92.8% and 81.9%, respectively, in 3 months, 6 months and 12 months after being discharged from hospital.	Discharge, age, education.
Yanget al(2012)28	Two-group comparison study	N=403, age range: 48–84, average age: 66.98±7.98, female 161 (40%)	Guiyang, Guizhou Province, China.	Morisky Medication Adherence Questionnaire.	Medication adherence can be different among men and women. Female participants had better medication adherence in aspirin, beta-blockers and ACEI/angiotensin II receptor blockers. There was no significant difference between female and male participants in adherence to statins.	Gender.
Huanget al(2014)*30	Longitudinal study	N=262, 51 female (19.5%)	Nanning City, Guangxi Province, China.	Morisky Green Levine Test.	6 months after the PCI, 48.9% of the participants did not adhere to their antiplatelets. 12 months after the PCI, 62.9% participants did not adhere to their antiplatelets.	Income, education, discharge, medication cost/insurance.
Zhangand Chen(2011)*31	Retrospective analysis study	N=500, average age: 72±8.82, female 228 (45.6%)	Chongqing, China.	Did not use instrument. Participants were interviewed within 12 months after PCI. If a participant told he/she has the same medication as he/she has at the time of discharge, the participant was regarded as adherent.	All participants adhered to their medications at baseline. After being discharged from hospital, the adherence rate started to decrease. 185 (37%) participants did not adhere to their medications. Among the 185 participants, nearly 97% stopped their medications 6 months later after being discharged or even earlier.	Comorbidity, discharge, medication cost/insurance, education.
Li (2013)*32	Cross-sectional study	N=271, age range: from 39 to 71, female 100	Wuding County, Yunnan Province, China.	Did not use instrument. Participants were identified as non-adherent as long as they missed one dose, changed the dosage/frequency or made self-decision to stop medication.	87.82% participants did not adhere to prescribed medications. Of these participants, 22.9% changed their medications’ dosage or frequency, 30.6% missed at least one dose of medication, and 34.3% stopped physician-prescribed medications and replaced them by other medications.	Income, discharge.
Liuet al(2017)33	An observational cohort study	N=404, average age: 58±10, female 99 (24.5%)	Beijing, China.	Did not use instrument. Medication adherence was assessed by whether participants stopped taking prescribed medication—ticagrelor.	39.1% participants did not adhere to their medications. Economic reasons and haemorrhagic event were the main causes of non-adherence to ticagrelor.	Adverse effects, income.
Chen et al (2015)35	Longitudinal study	N=512, female 302	Jiangsu Province, China.	Did not use measurement. Medication adherence was defined as taking the same category of drugs at discharge during the follow-up period.	Compared with those with preserved left ventricular ejection fraction (LVEF), patients with reduced LVEF have lower medication adherence.	Comorbidity.
Atkins et al (2017)36	A cohort analysis	N=15 140, female 3651 (24.11%)	70 hospitals from 17 provinces of China.	Did not use instrument. Medication adherence was assessed by the rate of medication usage among participants.	Use of cardioprotective medications declines over time after discharge.	Discharge.
Du et al (2016)38	Randomised controlled trial	N=964, female 264	Zhengzhou, Henan Province, China.	Did not mention.	Intervention group had better medication adherence than the control group.	Follow-up phone call.
Liet al(2012)39	Randomised controlled trial	N=100, female 43	Xi’an, Shaanxi Province, China.	Proportion of days covered (PDC) was used to measure medication adherence. PDC=number of days when medications were taken/number of days being interviewed.	Intervention group had significantly better medication adherence than the control group.	Follow-up phone call, medication memo card, educational session/individual face-to-face education.
Cao et al (2017)43	Randomised controlled trial	N=236, average age: 68.10, female 64 (27.12%)	Chengdu, Sichuan Province, China.	MMAS-8.	Intervention group had significantly higher medication adherence scores than control group at 30 days and 90 days after discharge.	Educational session/individual face-to-face education, follow-up phone call.
Jiang et al (2007)40	Randomised controlled trial	N=167, female 48	Chengdu, Sichuan Province, China.	The self-reported drug compliance scale, a 5-point Likert scale ranging from 1 (totally drug refusal) to 5 (100% drug compliance). This instrument is reliable and valid.	Medication adherence was decreased over time, but to a significantly lesser extent in intervention group.	Educational session/individual face-to-face education, booklet.
Zhao and Wong (2009)44	Randomised controlled trial	N=200, female 53 (53%)	Tianjin, China.	Did not mention the name of the survey, but the authors explained the content validity of the instrument was confirmed by experts in the study team.	Medication adherence was not significantly different between the control group and the intervention group at baseline, but the intervention group participants’ adherence was better and became significant in weeks 4 and 12.	Educational session/individual face-to-face education.
Zhao et al (2015)41	Randomised controlled trial	N=90, did not mention female	Zhengzhou, Henan Province, China.	Questionnaire, did not mention the name of the questionnaire, and did not mention its reliability and validity.	Medication adherence was significantly better in the intervention group than in the control group.	Educational session/individual face-to-face education, follow-up phone call.
Wuet al(2012)45	Two-group comparison study	N=110, female 22 (20%)	Chengdu, Sichuan Province, China.	Did not use measurement. Interviewed participants to see if they were still taking their medication.	Medication adherence of the intensive group was much better than the control group.	Booklet.
Zhaoet al(2015)42	Randomised controlled trial	N=120, female 48	Zhengzhou, Henan Province, China.	Did not use instrument.	Intervention group had better medication adherence than the control group.	Booklet, educational session/individual face-to-face education, follow-up phone call.
Fang and Li (2016)46	Randomised controlled trial	N=280, age range: 38–69, female 80 (28.58%)	Chengdu, Sichuan Province, China.	MMAS-4.	Participants in the intervention group of using WeChat had better medication adherence.	Short message service, mobile app.

Articles marked with * were retrieved from Chinese database, the China National Knowledge Infrastructure. Articles in bold were written in Chinese.

ACEI, ACE inhibitor; CHD, coronary heart disease; LDL-C, low-density lipoprotein-cholesterol; MMAS-4, Four-Item Morisky Medication Adherence Scale; MMAS-8, Eight-Item Morisky Medication Adherence Scale; PCI, percutaneous coronary intervention.