ORIGINAL ARTICLE

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DIABETIC HYPERTENSIVE CONTROL AND TREATMENT: A DESCRIPTIVE REPORT FROM THE AUDIT DIABETES CONTROL AND MANAGEMENT (ADCM) REGISTRY

BH Chew¹ MFamMed, I Mastura² MFamMed, AT Cheong¹ MFamMed, SAR Syed Alwi³ MFamMed
¹Department of Family Medicine, Universiti Putra Malaysia (Chew Boon How, Cheong Ai Theng)
²Klinik Kesihatan Seremban 2, Negeri Sembilan (Mastura Ismail)
³Department of Family Medicine, Universiti Malaysia Sarawak (Syed Alwi Syed Abdul Rahman)

Address for correspondence: Dr Chew Boon How, Department of Family Medicine, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia. Tel: +603-8947 2520, Fax: +603-8947 2328, Email: chewbh@medic.upm.edu.my

Funding: This project was supported by Ministry of Health, Malaysia.

BACKGROUND

Hypertension is a common co-morbidity in 65% of patients with diabetes mellitus (DM).^1-3 In type 2 diabetes (T2D), hypertension is often part of metabolic syndrome whereas in type 1 diabetes (T1D), hypertension often indicates the co-existence of diabetic  nephropathy.^4-7 Poorly controlled hypertension leads to heightened and accelerated nephropathy, cerebrovascular accidents, three-fold increase of atherosclerosis and heart diseases, retinopathy, poor quality of life and prematured death.^8-13 Micro and macrovascular complications are more common in diabetic patients who also have hypertension. These patients have two-fold increased risk of cardiovascular mortality compared to patients with diabetes alone. Studies have shown that intensive blood pressure (BP) control has a beneficial effect in decreasing the rate of progression of these complications.^14-16

The United Kingdom Prospective Diabetes Study (UKPDS 38) had shown that patients with good BP control (mean BP of 144/82 mmHg) had 25-50% less risk of developing cardiovascular complications compared to patients with not so well controlled BP (mean BP of 154/87 mmHg).¹⁵ Adequate BP control was reported to be the most cost-effective treatment to reduce cardiovascular complications in patients with DM. Current literature indicates that management of hypertension in diabetic patients is generally far from satisfactory.^17-21

There are many evidence-based guidelines for management of hypertension in patients with DM. These guidelines emphasize on intensive BP control with combined drug therapy.^{14, 22, 23} Renin-angiotensin system inhibitors are the preferred antihypertensive drugs of choice since a number of clinical trials have documented the benefits of these drugs in diabetic patients.^{14-16, 22} Periodic audit and awareness of clinical performance in diabetic care is essential towards prevention of diabetic complications. This study assessed the control and treatment of hypertension in patients with diabetes from the database of Audit of Diabetes Control and Management (ADCM).

METHOD

AUDIT OF DIABETES CONTROL AND MANAGEMENT (ADCM) REGISTRY

ADCM is a multi-centred observational cohort study that was started in May 2008 in the state of Negeri Sembilan and will later include other states in Malaysia. The aim of this project is to gather information to monitor provision of diabetic care in Malaysia, to improve treatment outcomes, to help with budget planning, to facilitate research activities and to enhance health education for physicians and patients on the potential serious impacts of this chronic disease on the nation.^24-27

All government health clinics and hospitals were invited to participate in this project. These clinics are mainly managed by medical officers and paramedics such as medical assistants, staff nurses, community nurses, nutritionists and physiotherapists.²⁸ Some bigger health clinics are supervised by resident family medicine specialists and qualified pharmacists.²⁸ Trained physicians and paramedical staff of these health clinics (termed as source data providers (SDP)) were briefed and instructed on how to register all newly diagnosed cases of DM of aged 18 years and above and how to enter follow-up information on the status of their diabetes. An online standard case record form (CRF) is available in the ADCM website. Information required includes demographic data, duration of diabetes, clinical examination findings including BP reading, treatment modalities, as well as various risk factors and diabetic complications. To maintain confidentiality, certain security procedures are required for SDP to gain access to the database.²⁹

Diagnosis for new cases of DM is based on WHO criteria. Diagnosis for follow up cases is based on their current treatments that include lifestyle modification, oral hypoglycaemic drugs or insulin injections. Hypertension is diagnosed when there is persistent elevation of systolic BP >130 mmHg and/or diastolic BP >80 mmHg on two or more occasions as recommended in the National Clinical Practice Guidelines (CPG).³⁰ BP readings that were recorded most recently were analysed in this study. Good BP control is considered as BP ≤130/80 mmHg. Data collected is analysed by a secretariat based at Clinical Research Centre (CRC), Hospital Kuala Lumpur with the use of Data Analysis and Statistical Software (Stata) version 9.

Access to ACDM database for the purpose of writing this paper has received approval from Medical Research Ethics Committee (MREC), Ministry of Health, Malaysia.

RESULTS

Till 31st December 2008, there were a total of 81 health centres and hospitals that participated in this audit. Altogether there were 20 646 cases registered. About two third of them, 13 417 cases (65%) were reported to have hypertension. 19 484 (94.4%) had their BP recorded and out of these, 11 414 (58.5%) were found to have BP >130/80 mmHg.

Majority of cases (89.6%) were from Negeri Sembilan; 9.8% were from Selangor. Most of the cases registered (99.2%) were of T2D.  56.8% of cases were female; 56.6% were Malays, 19.5% were Chinese, 22.5% were Indians and 0.2% were of other races (Table 1). Mean age of patients was 58.0 years (SD 11.49); 76.9% of patients were aged 50 years and above. 82% of cases had body mass index (BMI) in the overweight category (BMI ≥23 kgm²); 42.3% in the obese category (BMI ≥27.5 kgm²). Mean age at diagnosis of diabetes was 54.8 years (SD 11.47) and mean duration of diabetes was 4.7 years (SD 4.20) (Table 2).

Table 1: Demographic profile of the T2D patients

Profile	Number (%)
Gender	20 646 (100)
Male	8687 (42.1)
Female	11 722 (56.8)
Not stated	237 (1.1)
Ethnicity	20 646 (100)
Malay	11 694 (56.6)
Chinese	4026 (19.5)
Indian	4637 (22.5)
Other Malaysian	48 (0.2)
Non-Malaysian	7 (0.03)
Not stated	234 (1.1)
Age groups (years)	20 646 (100)
<30	178 (0.9)
30-49	4423 (21.4)
50-69	12 424 (60.2)
≥70	3456 (16.7)
Not stated	165 (0.8)

Table 2: Duration of T2D

Duration of diabetes	Number (%)
<5 years	11 276 (54.6)
5-10 years	5672 (27.5)
>10 years	3356 (16.3)
Not stated	342 (1.7)
Total	20 646 (100)

Mean systolic and diastolic BP were 137.7 mmHg (SD 19.56) and 80.1 mmHg (SD 10.51) respectively. There were significant associations (Chi-square test, p<0.001) between each of these independent variables: ethnicity, age groups and duration of diabetes with target BP ≤130/80 mmHg. More Indians (45.9%) achieved target BP ≤130/80 mmHg as compared to the Malays (41.9%) and Chinese (34.8%). The older the patients, the lesser the percentage that achieved target BP ≤130/80 mmHg; 36.2% of age group ≥70 years achieved the target as compared to 42.3% and 59.3% of age groups 30-69 years and <30 years  respectively (Table 3). Longer duration of diabetes corresponds to lesser percentage that achieved the target BP; 39.1% of cases with diabetes >10 years attained BP ≤130/80 mmHg as compared to 42.1% and 41.8% of those who have diabetes 5-10 years and <5 years respectively (Table 3).

Table 3: Proportion of patients controlled to target blood pressure according to age groups and duration of diabetes

Age group	BP ≤130/ 80 mmHg, n (%)		Total, n (%)
	No	Yes
15-19	2 (16.7)	10 (83.3)	12 (100)
20-24	17 (42.5)	23 (57.5)	40 (100)
25-29	49 (42.6)	66 (57.4)	115 (100)
30-34	102 (42.0)	141 (58.0)	243 (100)
35-39	258 (45.3)	311 (54.7)	569 (100)
40-44	607 (49.3)	623 (50.7)	1230 (100)
45-49	1129 (52.4)	1027 (47.6)	2156 (100)
50-54	1745 (56.4)	1350 (43.6)	3095 (100)
55-59	2156 (60.0)	1439 (40.0)	3595 (100)
60-64	1771 (62.5)	1063 (37.5)	2834 (100)
65-69	1525 (64.1)	853 (35.9)	2378 (100)
70-74	1138 (64.3)	633 (35.7)	1771 (100)
75-79	590 (63.6)	338 (36.4)	928 (100)
>80	325 (62.7)	193 (37.3)	518 (100)
Total	11 414 (58.6)	8070 (41.4)	19 484 (100)
Duration of diabetes	No	Yes	Total
<5 years	6331 (58.2)	4541 (41.8)	10 872 (100)
5-10 years	3089 (57.9)	2248 (42.1)	5337 (100)
>10 years	1891 (60.9)	1214 (39.1)	3105 (100)
Total	11 311 (58.6)	8003 (41.4)	19 314 (100)