Cost-effectiveness of RAMP-HT for Patients With Uncontrolled Hypertension in Hong Kong

Hypertension (HT) is an important risk factor for stroke, coronary heart disease (CHD), heart failure and renal diseases, and the leading risk factor of global disease burden. A multitude of interventions have proven efficacy in lowering blood pressure and reducing long term HT complications, including pharmacologic treatment, DASH diet (Dietary Approaches to Stop Hypertension), exercise, weight reduction, smoking cessation, alcohol moderation and self-monitoring of blood pressure.

Objectives:

To evaluate long-term effectiveness and cost-effectiveness of Risk-Assessment-and-Management-Programme-for-Hypertension (RAMP-HT), a multi-disciplinary structured service to enhance quality of hypertension care in primary care compared to usual care

Hypotheses:

1. RAMP-HT is effective in reducing HT complications, based on previous results showing RAMP-HT was effective in improving patients' blood pressure
2. RAMP-HT is cost-effective

Design and Subjects:

Retrospective study of 5-year longitudinal data on matched cohorts of public primary care patients with uncontrolled HT under RAMP-HT and usual care will be conducted to evaluate long-term effectiveness and direct medical costs. Results from the long-term effectiveness and costing analyses will be applied to Markov modeling to determine the life time cost-effectiveness of RAMP-HT.

Main outcome measures:

1. 5-year incidence of cardiovascular complications
2. Direct medical costs of RAMP-HT and usual care HT patients
3. Incremental cost-effectiveness ratio (ICER) of cost per quality-adjusted life year (QALY) gained by RAMP-HT compared to usual care

Data analysis:

Cox regression will be performed to estimate the effect of RAMP-HT on the development of HT complication adjusted for baseline covariates. Descriptive statistics will be used to calculate costs of RAMP-HT and annual direct medical costs for HT patients. Markov modeling will be used to simulate 2 patient cohorts (RAMP-HT versus usual care) to estimate the respective lifetime direct medical costs and QALY gained/person. Cost/QALY of RAMP-HT will be compared to that of usual care to determine the ICER.

Expected results:

The results can provide evidence on the effectiveness and cost-effectiveness of RAMP-HT for primary care patients with uncontrolled HT, which can inform health policy and service planning.

Aim and objectives:

The aim of this study is to evaluate the cost-effectiveness of the RAMP-HT of the HA in primary care patients with uncontrolled hypertension.

The objectives are to:

1. Evaluate the long term (5-year) effectiveness of RAMP-HT compared to usual care in reducing cardiovascular complications, end-stage renal disease and all-cause mortalities in a cohort of primary care patients with uncontrolled hypertension at baseline
2. Estimate the direct medical cost of RAMP-HT and other health services among primary care HT patients with or without complications
3. Evaluate the cost-effectiveness of RAMP-HT, compared to usual care, in gaining one QALY in primary care patients with uncontrolled hypertension

Hypotheses:

1. RAMP-HT is more effective in reducing 5-year cardiovascular complications, end stage renal disease and all-cause mortality among primary care patients with uncontrolled hypertension compared to usual care
2. The direct medical cost of RAMP-HT patients, for the same disease complication status, is not higher than that of usual care except for the RAMP-HT cost
3. The direct medical cost of HT patients with one or more complications is higher than that of HT patients without any complication
4. RAMP-HT is cost-effective compared to usual care, i.e. ICER per QALY gained is below the threshold value of 1 annual GDP (Gross Domestic Product) per capita of Hong Kong, which is the benchmark recommended by the World Health Organization

Eligibility Criteria:
Inclusion criteria:

1. Age ≥ 18 years old and \< 80 years old
2. Coded with ICPC-2 of K86 on or before baseline\*
3. Had uncontrolled blood pressure (i.e. average Systolic Blood Pressure (SBP) ≥ 140mmHg OR Diastolic Blood Pressure (DBP) ≥ 90mmHg between 6 months before and 3 months after baseline\*)

Exclusion criteria:

1. Patients who had a diagnosis of any HT complications defined by relevant ICPC-2 and/or ICD-9-CM diagnosis codes on or before baseline\*
2. Patients diagnosed to have Diabetes Mellitus (DM) on or before 31 March 2017, defined by ICPC-2 codes of T89 or T90
3. Patients exclusively managed by Specialist Out-Patient Clinic (SOPC) on or before baseline\*

   * Baseline: date of RAMP-HT enrolment for RAMP-HT cohort, and 31 March 2012 for usual care cohort