Distribution characteristics and factors influencing oral warfarin adherence in patients after heart valve replacement

Figures & data

Table 1 Baseline characteristics of the study sample

Characteristics	Total	Men	Women
Number of patients followed up
Patients followed up for 2 years (n)	2,128	993	1,135
Number of patients lost to follow-up	59	28	31
Age (mean±SD, years)	56±7.1	53±8.4	59±9.1
Living situation (n, %)
Urban	985 (46.3)	417 (42.0)	568 (50.0)*
Rural	1,143 (53.7)	576 (58.0)	567 (50.0)
Ethnicity (n, %)
Han	2,111 (99.2)	983 (99.0)	1,128 (99.4)
Other	17 (0.8)	10 (1.0)	7 (0.6)**
Education (n, %)
Elementary school or lower	1,110 (52.2)	456 (45.9)	654 (57.6)**
Intermediate school or higher	1,018 (47.8)	537 (54.1)	481 (42.4)*
Diabetes (n, %)	872 (40.9)	363 (36.6)	509 (44.8)**
Hypertension (n, %)	631 (29.7)	355 (35.7)	276 (24.3)*
Smoking (n, %)	586 (27.5)	547 (55.0)	39 (3.4)*
Type of surgery (n, %)
AVR only	738 (34.7)	357 (35.9)	381 (33.6)
MVR only	985 (46.3)	437 (44.0)	548 (48.3)
AVR and MVR	405 (19.0)	216 (21.8)	189 (16.7)*

Note: Compared with male,

* P<0.05,

** P<0.01.

Abbreviations: AVR, aortic valve replacement; MVR, Mitral valve replacement.

Table 2 Baseline characteristics of adherence to medical advice among artificial mechanical heart valve replacement patients at 2-year follow-up

Type of medical advice adherence	Number of patients (n)	Adherence rate (%)
Adherence to prescribed timing	2,017	94.8
Adherence to prescribed dose	1,989	93.5
Adherence to regular reexamination	1,954	90.8
All 3 of the above	1,847	86.8
Any 2 of the above	160	7.5
Any 1 of the above	121	5.7

Table 3 Comparison of adherence to medical advice among artificial mechanical heart valve replacement patients of different genders at 2-year follow-up (n, [%])

Gender	n	Adherence to prescribed timing	Adherence to prescribed dose	Adherence to regular reexamination
Male	993	956 (96.3)	886 (89.2)	901 (90.1)
Female	1,135	1,087 (95.8)	1,091 (96.1)*	1,107 (97.5)**

Note: Compared with male,

* P<0.05,

** P<0.01.

Table 4 Comparison of adherence to medical advice among artificial mechanical heart valve replacement patients of different ages at 2-year follow-up (n, [%])

Age	n	Adherence to prescribed timing	Adherence to prescribed dose	Adherence to regular reexamination
<18 years	2	2 (100)	2 (100)	2 (100)
18–60 years	1,825	1,737 (95.2)	1,668 (91.4)	1,606 (88.0)
≥60 years	301	289 (96.1)	296 (98.3)*	290 (96.5)*

Note: Compared with 18–60 years of age group,

* P<0.05.

Table 5 Comparison of adherence to medical advice among artificial mechanical heart valve replacement patients of different educational levels at 2-year follow-up (n, [%])

Educational attainment	n	Adherence to prescribed timing	Adherence to prescribed dose	Adherence to regular reexamination
Elementary school or lower	1,115	1,051 (94.3)	980 (87.9)	894 (80.2)
Intermediate school or higher	1,013	966 (95.4)	991 (97.8)*	978 (96.6)**

Note: Compared with elementary school or lower group,

* P<0.05,

** P<0.01.

Table 6 Comparison of adherence to medical advice among artificial mechanical heart valve replacement patients of different residence types at 2-year follow-up (n, [%])

Type of residence	n	Adherence to prescribed timing	Adherence to prescribed dose	Adherence to regular reexamination
Urban	997	965 (96.8)	976 (97.9)	929 (93.2)
Rural	1,131	1,075 (95.1)	1,002 (88.6)*	1,023 (90.5)

Note: Compared with urban resident group,

* P<0.05.

Table 7 Effects on oral warfarin anticoagulation adherence among heart valve replacement patients (n, [%])

Factor	Good adherence group (n=1,613)	Poor adherence group (n=515)
Male	554 (34.3)	439 (85.2)*
Aged>60 years	270 (16.7)	31 (6.0)*
Han ethnicity	1,601 (99.3)	510 (99.1)
Rural resident	757 (46.9)	386 (75.1)*
Intermediate school	809 (50.2)	209 (40.6)**
education or higher
Diabetes (n, %)	668 (41.4)	204 (39.6)
Hypertension (n, %)	471 (29.2)	160 (31.1)
Smoking	439 (27.2)	147 (28.5)
Type of surgery (n)
AVR only (n=738)	379 (51.4)	359 (48.6)
MVR only (n=985)	481 (48.9)	504 (51.1)
AVR and MVR (n=405)	206 (50.8)	199 (49.2)

Note: Compared with good adherence group,

* P<0.05,

** P<0.01.

Abbreviations: AVR, aortic valve replacement; MVR, Mitral valve replacement.

Table 8 Variable coding

Variable	Category	Frequency	Parameter coding
Dependent variable coding
Adherence to medical advice among patients	Yes	1,820	1
	No	308	0
Independent variables coding
Gender	Male	993	1
	Female	1,135	0
Age (years)	≤60	1,827	1
	>60	301	0
Ethnicity	Han ethnicity	2,111	1
	Ethnic minority	17	0
Type of residence	Urban	985	1
	Rural	1,143	0
Educational attainment	Elementary school or lower	1,110	1
	Intermediate school or higher	1,018	0
History of smoking	No	1,542	1
	Yes	586	0

Note: The independent variable had a binary variable value, and was represented by 1 or 0.

Table 9 Variables in the equation

	B	SE	Wald	df	P-value	Exp(B)	95% CI for Exp(B)
							Lower	Upper
Gender (1)	−2.511	0.161	241.982	1	0.000	0.081	0.059	0.111
Age (1)	0.744	0.242	9.488	1	0.002	2.104	1.310	3.382
Ethnicity (1)	−0.152	0.694	0.048	1	0.826	0.859	0.220	3.348
Type of residence (1)	2.100	0.154	186.605	1	0.000	8.170	6.039	11.043
Educational attainment (1)	0.346	0.139	6.171	1	0.013	1.414	1.076	1.856
Smoking (1)	−0.308	0.186	2.731	1	0.098	0.735	0.510	1.058

Note: Variable(s) entered on step 1: gender, age, ethnicity, type of residence, educational attainment, smoking.