Short-term effects of a pay-for-performance programme for diabetes in a primary care setting: an observational study

Figures & data

Table 1. Descriptive data for all patients in the NDR for the study and reference county in 2010 and 2011 (aged 18–79).

	Study county			Reference county
Year	2010	2011	p 2010 vs. 2011	2010	2011	p 2010 vs. 2011	p (diff. 2011–2010)^3
n^1	39 268	44 785		26812	32 804
Age	64.4 (10.2)***	64.3 (10.3)**	0.732	64.1 (10.2)	64.1 (10.3)	0.391	–
Sex (% female)	42.0	41.7	0.370	41.6	41.3	0.467	–
Diabetes duration	8.01 (7.55)***	8.12 (7.71)***	0.049	7.73 (7.23)	7.87 (7.42)	0.026	–
BMI	30.2 (5.5)***	30.2 (5.4)***	0.494	30.4 (5.5)	30.4 (5.5)	0.758	–
Smoking (%)	17.6***	17.4***	0.475	18.8	18.6	0.440	–
Albuminuria (%)	26.9***	23.1	<0.001	22.1	22.7	0.174	<0.001
Microalbuminuria	19.7***	17.4***	<0.001	14.9	15.9	0.014	<0.001
Macroalbuminuria	7.7	7.2	0.012	7.7	7.5	0.640	0.002
HbA1c
mmol/mol	53.5 (13.2)***	52.9 (13.4)***	<0.001	54.1 (13.1)	53.8 (13.5)	0.001	0.139
<52 mmol/mol (%)^2	53.5***	56.6***	<0.001	51.9	53.4	<0.001	<0.001
>72 mmol/mol (%)##	8.4**	8.5***	0.602	9.0	9.2	0.385	0.970
Blood pressure:
Systolic, mm Hg	134.8 (15.9)***	133.8 (15.7)***	<0.001	135.7 (15.9)	135.6 (15.7)	0.319	<0.001
Diastolic, mm Hg	76.7 (9.6)**	76.4 (9.7)*	<0.001	76.5 (9.5)	76.6 (9.6)	0.299	<0.001
<130/80 (%)	23.7***	28.0***	<0.001	22.3	22.2	0.718	<0.001
<140/90 (%)	72.5***	74.6***	<0.001	70.8	71.4	0.132	<0.001
LDL cholesterol
mmol/l	2.71 (0.89)***	2.68 (0.91)***	<0.001	2.68 (0.93)	2.65 (0.94)	0.004	0.139
<2.5 mmol/l (%)	45.4***	47.3*	<0.001	47.0	48.3	0.008	<0.001

Notes: Mean (SD) and frequencies (%).

1 Total number of patients who fulfil the inclusion criteria regardless of whether data are complete. Thus, n may be lower for an individual variable. The minimum number of patients evaluated for an individual variable was 27 578 in the study county and 19 052 in the reference county for LDL cholesterol in 2010. ²<52 mmol/mol – HbA1c cutoff for payment, >72 mmol/mol – HbA1c level used in the NDR for poorly controlled diabetes with a significantly increased risk of complications. ³p-values calculated with paired data in the county.

***p ≤ 0.001,

**p ≤ 0.01,

*p ≤ 0.05 for the difference between the two counties in 2010 and 2011. BMI = body mass index; HbA1c = glycated haemoglobin; LDL: = low-density lipoprotein.

Table 2. Descriptive and outcome data for patients in the study county in 2011 with DM duration of at least two years broken down into two groups: (1) patients already in the register (existing patients) – entered in 2011 and 2009/2010); (2) new patients in the register – entered in 2011 but not 2009–2010: Crude data and adjusted for diabetes duration, age, and sex.

			Adjusted values^1
	Existing patients n = 30 002, mean	New patients n = 2663, mean	Existing patients, mean (95% CI)		New patients, mean (95% CI)		p
DM duration	9.5	11.5	–		–		–
Age (years)	65.2	61.6	–		–		–
Sex (% female)	41.5	42.9	–		–		–
BMI	30.1	29.8	–		–		–
HbA1c
mmol/mol	53.6	56.4	53.7	(53.6–53.9)	54.9	(54.4–55.4)	<0.001
<52 mmol/mol (%)	53.0	46.4	52.0	(51.4–52.7)	49.6	(47.5–51.8)	0.032
Blood pressure:
Systolic (mmHg)	133.6	134.0	133.6	(133.4–133.8)	134.8	(134.2–135.4)	<0.001
Diastolic (mmHg)	75.8	76.6	75.7	(75.6–75.8)	76.3	(75.9–76.7)	0.001
<130/80 (%)	28.8	28.0	29.0	(28.5–29.5)	26.5	(24.8–28.3)	0.010
LDL cholesterol
mmol/l	2.60	2.70	2.61	(2.60–2.62)	2.71	(2.68–2.75)	<0.001
<2.5 mmol/l (%)	50.9	45.7	50.7	(50.0–51.3)	45.2	(43.1–47.4)	<0.001
Microalbuminuria	18.0	19.8	16.9	(16.4–17.4)	18.7	(17.1–20.5)	0.041
Macroalbuminuria	7.6	9.6	6.6	(6.3–6.9)	8.0	(6.9–9.3)	0.012
Stroke (%)	13.0	9.1	11.4	(11.0–11.8)	9.0	(7.9–10.2)	0.001
Ischaemic heart disease (%)	24.3	20.1	21.0	(20.4–21.5)	19.6	(18.0–21.3)	0.122
Smoking (%)	16.6	18.5	16.2	(15.7–16.6)	16.1	(14.7–17.6)	0.913
Treatment:
Diet (%)	18.8	30.6	18.5	(18.0–18.9)	31.9	(30.1–33.8)	<0.001
Aspirin (%)	38.5	29.9	36.7	(36.1–37.3)	30.3	(28.4–32.2)	<0.001
Blood pressure (%)	77.4	62.9	78.7	(78.2–79.2)	68.3	(66.4–70.2)	<0.001
Lipid-lowering drugs (%)	65.9	48.3	65.9	(65.3–66.5)	50.2	(48.2–52.2)	<0.001

Notes: ¹ANCOVA/generalized linear models adjusted for sex, DM duration and age. BMI = body mass index; HbA1c = glycated haemoglobin; LDL = low density lipoprotein.

Table 3. Percentage of patients with entry of separate variable for the study and reference county in 2010 and 2011.

	Study county				Reference county
	2010	2011	Change (%)	p 2010 vs. 2011	2010	2011	Change (%)	p 2010 vs. 2011
n	39 268	44 785	14.0		26 812	32 804	22.3
Blood pressure	92.2***	94.5***	2.5	<0.001	86.8	85.7	–1.3	<0.001
HbA1c	94.4***	95.3***	1.0	<0.001	93.7	94.5	0.9	<0.001
LDL cholesterol	70.2**	82.7***	17.8	<0.001	71.1	69.7	–1.4	<0.001
Albuminuria	84.7***	84.5***	−0.2	0.302	69.7	67.1	–2.0	<0.001
Smoking	83.4***	91.8***	10.1	<0.001	86.9	85.9	–1.2	0.001
Entry of all 5 variables^1	56.7***	71.6***	26.3	<0.001	46.2	45.5	–1.5	0.058

Notes: Frequencies (%).

1 Information on HbA1c, BP, LDL cholesterol, albuminuria (yes/no), and smoking (yes/no).

***p ≤ 0.001,

**p ≤0.01,

*p ≤ 0.05 for difference between the counties in 2010 and 2011. HbA1c = glycated haemoglobin; LDL = low-density lipoprotein.

Table 4. Percentage (%) of patients in various BP categories for the study and reference county in 2010 and 2011.

	Study county				Reference county
	2010	2011	Change (%)	p 2010 vs. 2011	2010	2011	Change (%)	p 2010 vs. 2011
N^1	36 220	42 309	16.8		23 266	28 112	20.8
BP 130/80	5.1	4.7**	–7.8	0.005	4.9	5.1	4.1	0.330
BP divisible by 5	67.1***	61.2***	–8.8	<0.001	73.3	73.7	0.5	0.284
BP divisible by 10	38.3	33.7	–12.0	<0.001	38.5	40.0	3.9	<0.001
SBP 126–129	3.8***	5.9***	55.3	<0.001	2.4	2.5	4.2	0.809
SBP 131–134	3.2***	3.6***	12.5	0.001	2.5	2.5	–	0.974
DBP 76–79	6.0***	7.4***	16.7	<0.001	4.4	4.2	4.5	0.419
DBP 81–84	4.2***	4.4***	4.8	0.173	3.6	3.7	2.8	0.407

Notes: Frequencies (%).

1 Number of patients with information on blood pressure.

***p ≤ 0.001,

**p ≤0.01,

*p ≤ 0.05 for difference between the counties 2010 and 2011. BP = blood pressure; SBP = systolic blood pressure; DBP = diastolic blood pressure.

Figure 1. Mean systolic blood pressure in 2011 (Y-axis) for each 1 mm blood pressure reading in 2010 (X-axis) for the study and reference county (98.9% of patients had SBP of 100–180 in 2010).