25 Years after the Egyptian National Hypertension Project (NHP)

Contributed by M. Mohsen Ibrahim, MD
Sunday, 30 April 2017

President's Message

25 Years after the Egyptian National Hypertension Project (NHP)

This year the EHS is celebrating at its annual scientific meeting the 25th anniversary of the Egyptian NHP. This landmark study was the first of its kind in the developing world. I was privileged to be the principal investigator and the director of this national survey. In the following president message I will address four questions: 1. What is special about NHP? 2. How we did it? 3. What did we accomplish? 4. What was after NHP?

What is special about NHP?

  1. Originality: this is the first national hypertension survey in a developing country and the first to identify the magnitude of a health problem in Egypt at a national level. We were also able to define the prevalence of other cardiovascular risk factors and hypertensive complications among Egyptians.
  2. Plethora of data: data were collected not only about the prevalence of hypertension and rates of awareness, treatment and control, but also about the role of hypertension risk factors namely obesity, skin colour, socioeconomic status, social and job stress, salt intake and poor housing conditions. We have data about the prevalence of other cardiovascular risk factors such as diabetes mellitus, dyslipidemia and cigarette smoking.
  3. Quality control: what sets NHP apart from other surveys are the strict quality control measures, which made us feel confident that the data we have are accurate. Measures of quality control included training and certification of the research team, repeated blood pressure measurements (mean of four reading which reduces the random error), standardization of measurement methods through manual of operations, inspection of interviewer performance in the field by senior staff and revisiting of 5% of sample. Quality control measures at the central office included editing of data collections forms before entry into computer, range and cross validation. Important data were entered twice for matching.
  4. Motivation and enthusiasm of the NHP team through regular weekly meetings, and monthly plan of activities, stressing the importance of the project as a national service and as an important scientific work and the need and value of data collected.

How we did it?

  • Preparatory stage: during this stage the principle investigator recruited the project staff, communicated with the US side (NHLBI and John Hopkins University), completed site preparations, purchase of equipment, sample design and choice of survey areas (through expert epidemiologist), construction of questionnaire, manual of operations and other printed materials.
  • In this preparatory stage, we had training and certification of research team, formation of 12 sub-committees and conducted two pilot surveys.
  • Field operations: these were conducted in 21 sampling locations in 6 Egyptian governorates during the period December 1991 and May 1993. The survey was carried at two phases in a sample representing all Egyptian population, urban and rural, upper Egypt, Delta, Cairo, coastal and frontier governorates. It included all socioeconomic groups, men and women aged 25 years and older.

Following preparatory visits, during phase 1, hypertensive patients were identified. In phase 2, local health centers were established for detailed clinical and laboratory investigations including ECG, echocardiography, skin colour, optic fundus and biochemical blood and urine tests.

What did we accomplish?

  • Define, for the first time, the magnitude of hypertension problem in Egypt, the prevalence of hypertension risk factors, hypertensive complications and other cardiovascular risk factors among Egyptians.
  • The national estimate of hypertension was 26.3% with only 23.9% of hypertensives were receiving treatment and 37.5 % were aware of being hypertensive, while the control rate was only 8%. What was impressive is the differences in hypertension prevalence rate among different regions. The highest rates were in the greater Cairo area (31%) and the lowest were in the frontier governorates (19.9%). Sixty percent of the elderly Egyptians (> 65 years) were hypertensive.
  • Identify the prevalence of HT risk factors among Egyptians. These were aging, urbanization, obesity, social isolation, unemployment, low education and skin colour. Rates of obesity were 45.6% in hypertensive patients living in urban areas, whereas obesity was present 14.8% of rural hypertensive patients. Unemployment was present in 49.7% of hypertensives and in 25.3% of normotensives (these figures include men and women).
  • There was non-linear relationship between skin pigmentation measured by reflectance spectrophotometry and blood pressure in women but not in men.
  • LV diastolic dysfunction was the most common hypertensive complication present in 51.4% of patients, while LVH (LV mass index > 125g/m2 in males and >110 g/m2 in females) was present in 14.3% of hypertensives. Heart failure was present in 10.8% of hypertensive patients compared to 5.8% in age and gender matched normotensives.
  • The Egyptian investigators gained new experience in cardiovascular epidemiology regarding survey methods, questionnaire formulation, sampling and quality control.
  • The scientific benefits of NHP included identification of differences in prevalence figures of hypertension and its risk factors in a developing country compared with western and more developed countries. The data might help explain why certain populations are at a greater risk of developing hypertension and causes of regional differences. We recognized possible etiologic factors of hypertension such as body fat distribution, social stress and skin colour (in women).

What was after NHP?

Realizing the relative high prevalence rate of hypertension and cardiovascular risk factors among Egyptians, the following activities followed its termination:

  1. Establishment of the EHS (1995) and Pan Arab Hypertension Society (1998).
  2. Delta-C project: a nationwide cardiovascular prevention program (2005).
  3. Development of a national hypertension guidelines - for the first time in a developing country (1998). These guidelines were updated twice (2004, 2014).
  4. Physician education programs and public awareness campaigns (2001 and ongoing).
  5. Development of specialized hypertension clinics (2014).
  6. Joint research with drug industry in the field of hypertension (Ongoing).

Finally, this great project would not have been possible without the help of my staff at Cairo University and friends from USA, to whom I feel grateful.

President of the Egyptian Hypertension Society

M. Mohsen Ibrahim, MD

Prof. of Cardiology- Cairo University