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Coronary Heart Disease in Rural NSW:One Country Hospital’s Experience

A SURVEY OF PATIENTS ADMITTED WITH MYOCARDIAL INFARCTIONS TO THEARMIDALE AND NEW ENGLAND DISTRICT HOSPITAL, ARMIDALE NSW

Patricia Johnson

The Australian Journal of Rural Health ©Volume 1 Number 2, February 1993

Coronary Heat-t Disease in Rural NSW: One County Hospital’s Experience A SURVEY OF PATIENTS ADMITTED WITH MYOCARDIAL INFARCTIONS TO THE ARMDImE AND NEW ENGLAND DISTRICT HOSPITAL, ARMIDALZ NSW

by PATRICIA JOHNSON

ABSTRACT: Rural Australians are often viewed as living in idyllic surroundings and enjoying good health. A ‘retrospective study of 62 patients admitted to the Arrnidale and New England District Hospital between January 1989 and December 1990 with a diagnosis of myocardial infarction was carried out with the purpose of iden- tifying the characteristics and risk factor prevalence of those people who had suffered a myocardial infarction in a specific rural area demonstrated inconsistencies with this view. Age, gender, occupation, cigarette smok- ing, previous history of hypertension, weight, and serum cholesterol and triglyceride levels were examined to provide informarion for community based prevention programs and nursing discharge planning. Results were consistent with those of the National Heart Foundation (1988), and demonstrated a high incidence of smoking and a previous history of hypertension, which was particularly prevalent in blue collar workers/farmers. Con-

~ elusions were problematic regarding weight and levels of serum cholesterol and triglycerides as insufficient data was documented.

Coronary heart disease remains the leading cause of death in Western society, and was responsible for 32 639 (26.3 per cent) of the total number of deaths in Australia in 1989.’ The disease is caused by atherosclerosis, which is the accumulation of cholesterol and other fatty substances inside the arterial walls leading to a hardening and gradual obstruction of the arteries.’ Myocardial infarction, which is necrosis of myocardial tissue due to coronary occlusion, is most often caused by coronary atherosclerosis, although some rarer non atherosclerotic causes include dissecting aneurysm, polyarteritis, coronary artery spasm, coronary embolism, ergotamine abuse and cocaine abuse.3

Risk factors for atherosclerosis include hy- pertension, hypercholesterolaemia, cigarette smoking, obesity, diabetes mellitis, physical in- activity and increased stress levels.4 Heredity, age (increasing risk with each decade in age),

Patricia Johnson, BA (NE), Intensive Care Certificate (RNH), RN, is senior lecturer in the School of Health, University of New England-Armidale and acting director of the Nursing Research and Teaching Unit at Manning Base Hospital in Taree NSW

gender (males more at risk) and usage of the oral contraceptive pill have also been identified as having significance.5

Within Australia, coronary heart disease mortality rates are higher in blue collar workers, which includes farmers, as they tend to have higher blood pressure, a higher number of cigarette smokers, and are more overweight than white collar workers6 Mortality rates are also higher in the less educated compared with the more educated, perhaps due to a lack of knowledge by the former about risk factors, and in Australian born compared with non-Australian born people.6 Aborigines have been found to have mortality rates from coronary heart disease up to 5.4 times greater than those of the total population for males, and 3.9 times greater for females.’

Several of these factors have a significant impact on the health status of rural areas in Australia. The term rural is difficult to define, due to the diverse nature of many non-urban areas, and definitions have focused on geographical, demo- graphical, social and economic factors.s For the purposes of this study, the term rural is defined by exclusion as those areas with a combined

20 The Australian Journal of Rural Health

population of less than 80 000 persons. Risk factors associated with the development

of atherosclerosis that are of concern to rural Australians include age, gender, occupation, educational status, Aboriginality and nationality. Rural areas are over-represented in certain regions, especially rural towns, by the aged,9 are male dominated,” have large proportions of blue collar workers/farmers, often have less access to, and opportunity for, attaining higher levels of secondary education,” and have a lower proportion of mi- grants,” and a higher proportion of Aborigines’* than do urban areas. Health is a major concern for rural Australians, and studies have shown that rural area populations exhibit higher than aver- age levels of premature mortality and death through ischaemic heart disease.r2

Many of the risk factors for developing coronary heart disease are preventable, or at least modifiable, and it is extremely important to identify a rural community’s risk factors so as to aid in the de- velopment of primary prevention programs that are specifically targeted to meet the needs of that particular community. As the economic cost of myocardial infarction involves direct costs such as medical, hospital and pharmaceutical services, and indirect costs such as lost earnings due to premature death, early retirement or disability, it is also important to focus on preventative measures given the current economic climate, both of the rural and health sectors.

AIM OF THE STUDY

The aim of this study was to identify the charac- teristics of a specific sample of rural people who suffered a myocardial infarction and were admitted to a rural hospital for treatment, and to also identify any risk factors that may have a preventable component that could influence both preventa- tive and nursing discharge planning. As specific factors have previously been identified as being of particular significance to rural areas, this study chose to examine age, gender, occupation, ciga- rette smoking, weight and any previous history of hypertension. Serum cholesterol and triglyceride levels were also examined.

METHOD A retrospective study was carried out on the 62 people admitted to the Armidale and New Eng-

land District Hospital, N.S.W., between January 1989 and December 1990 with a diagnosis of acute myocardial infarction. The coronary care/intensive care/recovery unit of this hospital can provide cardiac monitoring and management for a maximum of 6 patients at any one time.

Occupation was classified according to the 1986 Australian Standard Classification of Occupa- tions.13 This method of classification consists of eight categories: Managers and Administrators, Professionals, Para-Professionals, Tradespersons, Clerks, Salespersons and Personal Service Workers, Plant and Machine Operators and Drivers, and Labourers and Related Workers. Blue collar workers were classified as those in categories 4 (Tradespersons), 7 (Plant and Machine Operators and Drivers) and 8 (Labourers and related workers which includes farmers). White collar workers were classified as those in the remaining five categories. A previous history of hypertension was indicated if the person was taking regular antihypertensive medication on hospital admission.

RESULTS

The sample consisted of 62 people. There were seven deaths, three females and four males, indi- cating a mortality rate of 11 per cent. Character- istics are outlined below.

1. Age and gender Ages ranged from 38 years to 84 years. Average age was 61 years. There were 44 males (71 per cent) and 18 females (29 per cent). Figure 1 (opposite) illustrates these findings.

2. Occupation There were 43 (69 per cent) blue collar workers and farmers, 13 (21 per cent) white collar work- ers, and six (10 per cent) unspecified, which comprised pensioners (three), and those unable to be classified due to undocumented notes (see Figure 2, opposite).

3. Cigarette smoking There were 45 (73 per cent) smokers, and 17 (27 per cent) non-smokers and ex-smokers.

4. Previous history of hypertension Thirty-seven (60 per cent) of people were currently taking regular antihypertensive medication when admitted. Medications included Beta-blockers, Calcium channed blockers, peripheral vaso-dilators

Volume 1, Number 2 - February 1993

Figure 1: Age and gender characteristics

21

q MALE •FEMP~LE

35 - 44 45 - 54 55 - 64 65 - 74 75-k GENDER

Figure 2: Occupation

Blue Collar1Farmer 69.4%

El ::::;, a White Collar 21 X m Unspecifed 9.7%

and A.C.E. inhibitors. Figure 3, on the next page, indicates the frequency

of the known risk factors of smoking and hyperten- sion among the sample under discussion.

Of those classified as blue collar workers and farmers, 37 (86 per cent) smoked, 28 (65 per cent) had a previous history of hypertension, 25 (58 per cent) both smoked and had a previous history of hypertension, and three (7 per cent) neither smoked nor had a previous history of hypertension. Of those classified as white collar workers, six (43 per cent) smoked, six (43 per cent) had a previous history of hypertension, three (23 per cent) both smoked and

had a previous history of hypertension, and four (3 1 per cent) neither smoked nor had a previous history of hypertension. Of those in the unspecified category, two (33 per cent) smoked, three (50 per cent) had a previous history of hypertension, one (17 per cent) both smoked and had a previous history of hyper- tension, and two (23 per cent) neither smoked nor had a previous history of hypertension.

5. Weight There are a number of ways of measuring body fat, and a widely used formula is the body mass index (BMI), which is calculated as follows:

22 The Australian Toumal of Rural Health

Figure 3: Cigarette smoking and previous history of hypertension

m Smoked m Hypertension

Both m Neither

Blue Collar IFarmer White collar Unspecified

BMI = weight (kgjlheight (in metres)’ rates between 10-15 per cent in the first month

As a general rule, a BMI less than 20 is under- weight, between 20-25 is desirable, between 25-30 is overweight and greater than 30 is ~bese.~ Body mass index was unable to be assessed on any of the sam- ple as weight and height were not measured.

6. Serum cholesterol and triglycerides These levels were only measured on 19 (31 per cent) of the sample. Of the 19 results obtained, 10 (53 per cent) had elevated serum cholesterol levels, and three (16 per cent) had elevated triglyceride levels.

DISCUSSION

The results of this study undertaken in a rural area highlighted the relevance of certain risk factors in the development of coronary heart disease and subsequent myocardial infarction for this sam- ple. Age and gender data showed that males out- numbered females by a ratio of nearly 2.5: 1, which is consistent with recent dataS3 Females outnum- bered males by a ratio of 2:l in the oldest age group, perhaps illustrating the fact that average life expectancy for females is 79 years, compared to 73 years for males6 The mortality rate of 11 per cent was consistent with reported mortality

after hospital admission.3 Occupational categories illustrated the increased

incidence of myocardial infarction in blue collar workers and farmers (69 per cent). This category had a higher number of cigarette smokers (86 per cent), a higher number of persons with a previ- ous history of hypertension (65 per cent), and a higher number of persons displaying both of these risk factors (58 per cent) than did the other two categories. These results are consistent with those of the National Heart Foundation 198g6 and highlight the need for community based programs that aim to target more specifically blue collar workers and farmers.

The prevalence of cigarette smokers in all categories is cause for concern, as the risk effects of smoking are well documented. Despite the known relationship between smoking and coro- nary heart disease, a survey by the National Heart Foundation in the mid 1980s found that 32 per cent of males and 25 per cent of females reported smoking on a regular basis.6 Even thought these rates are decreasing slowly for all age groups excepting teenage women6 they are still far too high and represent a significant risk factor.

Hypertension has been shown to be a major

Volume 1, Number 2 - February 1993 23

risk factor in the development of coronary heart disease.r4Sixty per cent (60 per cent) of the sam- ple had a history of hypertension before admission and were taking some form of antihypertensive medication. There are several possible explana- tions as to why these people still infarcted, in- cluding ineffective drug therapy, non compliance by patients, and the likelihood that a number of other risk factors were also involved such as smoking, obesity, and hypercholesterolaemia.

As weight and height were not measured, it was impossible to evaluate the level of obesity in the sample. This was unfortunate as further find- ings may have provided more knowledge of community risk factors. A recent risk factor prevalence study found that about 60 per cent of men and 50 per cent of women aged 45 years and over were overweight’, and losing excess weight is an accepted part of any program to lower coro- nary risk, as weight loss alone can significantly lower blood pressure and serum cholesterol levels’. It is extremely important that all patients admitted with myocardial infarction have their BMI measured during hospitalisation, so that those who are overweight can be referred for dietary con- sultation, and educated on the importance of a regular exercise program such as that recommended by the National Heart Foundation of Australia.ls

Similarly, it is impossible to draw any real conclusions from the small sub-sample that had serum cholesterol and triglyceride levels meas- ured, even though a very small majority did dis- play elevated serum cholesterol levels. It is important to measure serum cholesterol and triglyceride levels on all patients admitted with myocardial infarction, as it is recommended that all Australian adults should be aiming for a blood cholesterol level equal to or less than 5.5mmol/ L.r5 Those patients who have elevated levels can be educated about dietary modification, as most people can reduce their cholesterol level by fol- lowing a low fat diet.r5

CONCLUSION The limitations of retrospective studies were well illustrated by this particular study, as the patient records were not always fully documented and only certain factors were able to be examined. Pro- spective studies are capable of examining a greater number of factors, for example obesity, family

history, stress levels and knowledge of risk fac- tors, which can add further valuable information and thereby increase efficacy of care and aid in planning effective preventative and rehabilitation programs. The National Heart Foundation of Australia recommends that individual communi- ties identify their risk factor prevalence for coronary heart disease, and structure preventative and re- habilitation programs based on these flndings15. The high incidence of cigarette smoking, particulary in blue collar workers/fanners, combined with the prevalence of hypertension in this particular study, requires a community based program more spe- cifically targeted to this occupational group, so as to provide greater community awareness for all the population and aim to further reduce the incidence of myocardial infarction in the Armidale and district community.

REFERENCES l.National Heart Foundation of Australia. Heart Facts. 1989 2Dossey, B.M.,Guzzet@C.E.,Kenner,C.V. EssentialofCritical

Care Nursing. Philadelphia: J.B. Lippincott, 1990. 3.Thompson P.L. Myocardial Infarction. InTEOH (ed) Intensive

Care Manual. Sydney: Buttenvorths, 1990: 28-39. 4.Boruschek, A., & Boruschek, J. Heart Disease Prevention

Manual. Perth: FHP, 1987. 5Carlisle. C. Hunt, D., Sloman, G. Coronuv Care Workbook.

4th ed. Netley: Griffin Press. 1980. 6.National Heart Foundation of Australia. Heart Facts. 1988. 7.Thoma.s. N. Aboriginal Health-Current Status, Australian and

A’ew Zealand Journal of Medicine. 1984: 14:705-718. 8.Humphreys. I. Health Care in Rural Australia: Geographical

Implications. In Cullen, T., Dunn. P., Lawrence. G. (eds) Rural Health and Welfare in Australia, Centre for Rural ~--~-~__ Welfare Research, Charles Stur-~ersit~l990:10-27.

9.b~. P. Rural Older Persons: Some Issues and Implications. In Cullen, T., Dunn, P.,Lawrence, G. (eds). Rural Healrh

--

and Welfare in Australia. Centre for Rural Welfare Re- search, Charles Sturt University, 1990: 11 l-1 3 1.

lO.Musgrave, W.F. Economic, Demographic and other Influences, Trans. Rural AusfraIia .S~mposium. 6-8 July, 1987:1-6.

ll.Smith. N. Young People in Rural Communities. In Cullen. T.. Dunn, P., Lawrence, G. (eds) Rural Health and We/fare -- in Aztsfruli;iCentre for Rural Welfare Research, Charles Stun University, 1990:102-110.

12. Kellehear, A. A Critique of National Health Policies for Counny People. In Cullen, T., Dunn, P., Lawrence. G. (eds) Rural Health and Welfare in Australia. Centre for Rural Welfare Research, Charles Sturt University, 1990:28-40.

13Australian Standard Clnssificarion of Occupnrions Dicfion- ary. Canberra: AGPS. 1986.

14.Cranswick. R. Hypertension and the Heart Pafient Man- agement. September. 1988:45-54.

15.National Heart Foundation of Australia. How to Plan a Cardiac Rehabilitation Program. 1991.