Case-Based Training of Evidence-Based Clinical Practice in Primary Care and Decreased Mortality in Patients With Coronary Heart Disease

Anna Kiessling; Moira Lewitt; Peter Henriksson

doi:10.1370/afm.1248

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Figure 1.
Trial profile: patient selection, inclusion, participation, and follow-up.
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Figure 2.
Cumulative proportion of deceased patients in the intervention and control groups treated by general practitioners, and in the group treated by specialists.

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Table 1.

Baseline Characteristics of General Practitioners and Primary Health Care Centers

Characteristic	Intervention	Control
^a All of the general practitioners specialized in general medicine. None had a known relation to any of the physicians in the other group.
^b Calculated for individuals aged older than 16 years in 1995 (kSEK = 1,000 Swedish crowns).
General practitioners, No.^a	26	28
Age, mean (SD), y	47.0 (6.3)	46.4 (4.8)
Women, No. (%)	9 (35)	9 (32)
Patients per physician, median (range), No.	1 (0–4)	1 (0–5)
	No.	No.
Primary health care centers	7	7
Physicians per center
1–3	3	3
4–5	3	2
≥6	1	2
Inhabitants per center
≤4,999	2	2
5,000–9,999	2	3
≥10,000	3	2
Mean income per capita^b
≤149 kSEK	1	1
150–199 kSEK	5	4
≥200 kSEK	1	2
Location
Urban only	5	5
Mixed urban and rural	2	2

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Table 2.

Baseline Characteristics of Patients

		Group
Characteristic	Total (N=255)	Intervention (n=45)	Control (n=43)	P Value	Specialist (n=167)
BMI = body mass index; BP = blood pressure; CABG = coronary artery bypass grafting; CCS = Canadian Cardiovascular Society classification system of current angina pectoris symptoms; CHD = coronary heart disease; HDL=high-density lipoprotein; LDL=low-density lipoprotein; MI=myocardial infarction; PCI=percutaneous coronary intervention.
Notes: Patient group reflects the group to which the patient’s treating physician was assigned. Specialist denotes the group of patients treated by a specialist in cardiology or internal medicine.
^a Triglyceride values in millimoles per liter were converted to milligrams per deciliter by multiplying by 88.57. Other cholesterol values were converted to milligrams per deciliter by multiplying by 38.67.
^b Based on 44 patients having data for these measures.
^c Based on 250 patients having data for this measure.
Age, mean (SD), y	60.1 (7.5)	62.6 (6.1)	62.3 (7.4)	.93	59.0 (7.6)
Women, No. (%)	57 (22)	8 (18)	5 (12)	.55	44 (26)
Comorbidities, No. (%)
Diabetes	37 (15)	5 (11)	6 (14)	.76	26 (16)
Hypertension	67 (26)	16 (36)	10 (23)	.25	41 (25)
Other	71 (28)	11 (24)	12 (28)	.81	48 (29)
Current smoker, No. (%)	61 (24)	10 (23)	9 (21)	.89	42 (25)
BMI, mean (SD), kg/m²	28.0 (4.2)	28.1 (5.5)	27.2 (3.4)	.34	28.1 (3.9)
BP, mean (SD), mm Hg
Systolic	139 (20)	142 (19)	139 (20)	.59	138 (21)
Diastolic	84 (9)	84 (10)	85 (8)	.70	84 (9)
Lipid levels, mean (SD), mg/dL^a
Total cholesterol	247 (43)	244 (39)	240 (43)	–	247 (46)
Triglycerides	186 (97)	186 (106)	186 (89)	–	186 (97)
HDL cholesterol	46 (12)	46 (15)	43 (12)	–	46 (12)
LDL cholesterol	162 (39)	162 (31)	159 (39)	–	166 (39)
Medications, No. (%)
Acetyl salicylic acid	205 (80)	38^b (86)	33 (77)	.28	134 (80)
β-blocker	166 (65)	25 (56)	21 (49)	.50	119 (71)
Lipid-lowering drugs	49 (19)	6^b (14)	3 (7)	.48	40 (24)
Duration of CHD, mean (SD), y	6.0 (5.6)	5.6 (5.8)	6.2 (5.9)	.62	6.0 (5.4)
History, No. (%)
MI	167 (65)	29 (64)	23 (53)	.39	115 (69)
CABG	95 (37)	12 (27)	13 (30)	.81	70 (42)
PCI	29 (11)	2 (4)	3 (7)	.67	24 (14)
CCS class, No. (%)^c
0–1	147 (59)	25 (60)	29 (69)	.49	93 (56)
2–4	103 (41)	17 (40)	13 (31)	3	73 (44)

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Table 3.

Mortality and Cause of Death

		Group
Cause of Death	Total (N=255) No. (%)	Intervention (n=45) No. (%)	Control (n=43) No. (%)	P Value	Specialist (n=167) No. (%)
Notes: Cox regression analysis was used to compare the groups. P values are adjusted for group-randomized trials according to the method of Murray.¹⁸ The intraclass correlation coefficient (ICC) was 0.12 for all deaths, 0.14 for coronary heart disease deaths, and 0.14 for cardiovascular deaths. Results were confirmed by logistic regression analysis and the inclusion of the covariates age, sex, hypertension, smoking, and diabetes.
All deaths	68 (27)	10 (22)	19 (44)	.02	39 (23)
Cardiovascular deaths	43 (17)	7 (16)	14 (33)	.01	22 (13)
Coronary heart disease	36 (14)	5 (11)	12 (28)	.02	19 (11)
Other vascular cause	7 (3)	2 (4)	2 (5)	.37	3 (2)
Noncardiovascular deaths	25 (10)	3 (7)	5 (12)	.68	17 (10)
Neoplasia	15 (6)	2 (4)	2 (5)	.93	11 (7)
Other	10 (4)	1 (2)	3 (7)	.40	6 (4)

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The Article in Brief

Case-Based Training of Evidence-Based Clinical Practice in Primary Care and Decreased Mortality in Patients With Coronary Heart Disease

Anna Kiessling , and colleagues

Background This study is one of the first to evaluate the impact of physician continuing medical education on patient outcomes. Specifically, the study examined whether case-based training, designed to help general practitioners manage patients with hyperlipidemia (high levels of fat in the blood, such as cholesterol and triglycerides), increased 10-year survival in patients with coronary heart disease.

What This Study Found Patients of physicians who participated in case-based training had a 10-year mortality rate one-half that of patients whose physicians who didn�t take the training. In addition to a standard lecture and mailing of new evidence-based treatment guidelines received by all physicians who participated in the study, the physicians in the intervention group participated in small-group seminars, facilitated by a cardiologist, which encouraged the discussion of cases and active problem solving. After 10 years, 22 percent of the patients in the intervention group had died compared with 44 percent of patients in the control group, a difference mainly attributed to reduced cardiovascular mortality. The 22 percent mortality rate in the intervention group was comparable to the rate of 23 percent seen in patients treated by a comparison group of cardiology and internal medicine specialists.

Implications

Based on these findings, the authors call for case-based training to be tested in other areas of clinical practice.