Identification and resolution of drug therapy problems among hypertensive patients receiving care in a Nigerian Hospital - A pilot study

Background: An event involving drug therapy that actually or potentially interfers with the desired health outcomes is known as drug therapy problem.

Objective: The study aimed to identify and resolve potential drug related problems encountered among adult hypertensive patients receiving care in a Nigerian Tertiary Hospital. Methods: This was a prospective cross sectional study. The data were collected from the patients’ medical records using the Pharmaceutical Care Network Europe (PCNE) Classification tool Version 6.2 (PCNE, 2010). For each of the 171 medical records, the DTPs experienced within the study period were identified. Data were analyzed using the IBM Statistical Product and Service Solutions (SPSS) for Windows, Version 21.0 (IBM Corp, Version 21.0, and Armonk, NY, USA).

Results: Majority of the patients were above 65years of age 64(37.4%), while about half of the patients were females. A total of 644 drug therapy problems were identified. The major cause of DTP was prescribing error 189(29.3). Other causes of drug therapy problem identified in this study were inappropriate drug selection 122(18.9), no indication for drugs 52(8.1), inappropriate drug combination 87(13.6), new indication presented 61(9.5), dose too high 62(9.6), dose too low 44(6.8), wrong drug taken/administered 27(4.2). Majority of the interventions made were accepted 586(91.0%) while only 3(0.5%) of the interventions made were not accepted.

Conclusion: This study demonstrates that a pharmacist, with adequate training and support can play a vital role in identifying and resolving drug therapy problems. Also, there is a need for an educational intervention among prescribing physicians to update them regularly on hypertension guidelines.

An event involving drug therapy that actually or potentially interferes with the desired health outcomes is known as drug therapy problem [1]. Drug therpy problems is defined by the World Health Organization (WHO) as “any response to a drug which is noxious and unintended and which occurs at doses normally used in man for prophylaxis, diagnosis or therapy of disease, or for the modification of physiological function” [2]. Hypertension is the most common cardiovascular disease. In a surveyed carried out in 2009, hypertension was in 28% of American adults and 60% of adults 65 years or older [1]. The prevalence varies with age, race and education. According to some studies, 60% - 80% of both men and women will develop hypertension by age of 80 [3]. Analysis of the global burden of hypertension revealed that over 26% of the world’s adult population had hypertension in 2000, and has shown a rapid increase in prevalence affecting significant numbers of individuals in Sub-Saharan Africa [4].

Studies worldwide indicate that despite the availability of effective medical therapy, more than half of hypertensive patients on treatment have blood pressures over 140/90 mm Hg threshold [5]. This is mostly because of drug therapy problems which include but not limited to non-compliance, ADRs, improper drug selection and drug interactions.

The occurrence of a DTP among hypertensive patients could prevent or delay patients from achieving desired therapeutic goals [6]. It has been attributed to unnecessary over-prescription of drugs, substantial worsening of diseases, avoidable increases in hospital admission rates, and longer hospital stays leading to a significant medical burden [7]. As a result, substantial numbers of patients do not get the maximum benefit of medical treatment, resulting in poor health outcomes, lower quality of life, increased health care costs and erodes public confidence in health systems [8].

Objective

This study aimed to assess the Knowledge, attitude and practice towards hypertension among hypertensive patients receiving care in a Nigerian hospital.

Study design: This was a prospective study which involved the medical records of Adult hypertensive patients receiving care in a tertiary hospital in Kogi state, Nigeria.

Ethical committee approval: Ethical approval was obtained from the Health Research and Ethics Board of the Kogi State Specialist Hospital, Ministry of Health Kogi State before commencement of the study.

Eligibility criteria: The eligibility criteria included all the folders of hypertensive with Diabetes comorbidity outpatients who received prescription from the hospital within the study period (August-September 2019).

Sample size calculation: All folders that fell within the eligibility criteria were utilized for the study. A total of 171 patient folders were used.

Data collection

The data were collected from the patients’ medical records using the Pharmaceutical Care Network Europe (PCNE) Classification tool Version 6.2 (PCNE, 2010). For each of the 171 medical records, the DTPs experienced within the study period were identified. The demographic information such as age and gender were recorded. Other items documented were the drugs implicated in the therapy problems, type of drug therapy problem, cause of drug therapy problem (DTP), type of intervention and the outcome of intervention. The PCNE V 6.2 has 4 primary domains for problems, 8 primary domains for causes and 5 primary domains for interventions. On a more detailed level, there are 9 grouped sub-domains for problems, 37 grouped sub-domains for causes and 17 grouped sub-domains for interventions. The sub-domains are explanatory for the principal domains.

Data analysis

Data were analyzed using the IBM Statistical Product and Service Solutions (SPSS) for Windows, Version 21.0 (IBM Corp, Version 21.0, and Armonk, NY, USA).

Majority of the patients were above 65years of age 64(37.4%), while about half of the patients were females. Also, most of the patients were traders 62(36.3%), 146(85.4%) were married, 146(79.1%) were Christians by religion and 164(95.9%) were currently non-smokers as at the time of the study (Table 1).

A total of 644 drug therapy problems were identified. Some of the drugs involved in DTP were, methyl dopa, frusemide, Nifedipine, lisinoril, metformin, metronidazole, analgesics like diclofenac, ibuprofen and paracetamol (Table 2).

The major cause of DTP was prescribing error 189(29.3). Other causes of drug therapy problem identified in this study were inappropriate drug selection 122(18.9), no indication for drugs 52(8.1), inappropriate drug combination 87(13.6), new indication presented 61(9.5), drug too high 62(9.6), drug too low 44(6.8), wrong drug taken/administered 27(4.2) (Table 3).

Majority of interventions made were on drug level 288(44.7%), while 183(28.4%) were made on patient level. Also, 152(23.6%) of the interventions were made on prescriber level while 21(3.3%) of the DTPs had no intervention (Table 4).

Majority of the interventions made were accepted 586(91.0%) while only 3(0.5%) of the interventions made were not accepted (Table 5).

Various drug combinations were responsible for the DTPs which may have resulted to therapy failure or adverse drug reactions. The use of methyldopa with frusemide constituted the major drug therapy problems in this study. Majority of the identified DTPs were due to adverse reactions. Most of the respondents were above 65 years of age, female and taking more than two medications. This is supported by the findings that adverse drug reactions occur mainly in young and middle aged adults and are twice as common in women [10]. From this study, patients who were on more than one medication experiences DTP more than those that were on a single medication. The use of multiple medications predisposes patients to adverse drug reactions [11]. Most of the patients in this study were on more than three drugs. Some of these medications may also predispose the patients to other disease states as a study showed that the long duration of therapy with beta-2 agonists positively correlated with the incidence of hypertension [12]. Our findings establish that prescribing error and inappropriate drug combinations were the major cause of drug therapy problems. This contrasts the results obtained in a recent study on drug therapy problems in adult hypertensive patients where about 40% of the drug therapy problems were due to non-adherence to medication (66%) [13]. Several studies have shown that most DTPs (48.75%) were from potential drug interactions [14]. Pharmacists can help in the making the right choice of drugs and possible combinations. Also, counselling can improve patient adherence and the outcome of therapy [14]. Inappropriate drug selection may be due to inappropriate prescribing. Less than a quarter of the DTPs had no documented interventions which might have stemmed from poor attitudes to documentation and poor patient-care approach. From the interventions documented, more than three-quarter had known intervention outcomes. Poor drug history documentation may lead to medication errors [15]. Health professionals should document appropriately to minimize or eliminate medication errors. Pharmacists’ participation in medication history documentation might significantly increase the frequency and depth of medication history information documented [15].

This study demonstrates that a pharmacist, with adequate training and support can play a vital role in identifying and resolving drug therapy problems in the hospital. Also, there is a need for an educational intervention among prescribing physicians to always keep them abreast with the current hypertension guidelines.

1. Aguwa CN, Nworu CS. Hypertension. In Aguwa CN, ed. Therapeutic basis of clinical pharmacy in the tropics. 4th ed. Enugu, Nigeria: Snaap press ltd; 2012; 88-90.
2. Andros V, Egger A, Dua U. Blood pressure goal attainment according to JNC 7 guidelines and utilization of antihypertensive drug therapy in MCO patients with type 1 or type 2 diabetes. J Manag Care Pharm. 2002; 12: 303-309. PubMed: https://pubmed.ncbi.nlm.nih.gov/16792436/
3. Beckett NS, Peters R, Fletcher AE, Staessen JA, Liu L, et al. Treatment of hypertension in patients 80 years of age or older. N Engl J Med. 2008; 358: 1887. PubMed: https://pubmed.ncbi.nlm.nih.gov/18378519/
4. Gudina EK, Michael Y, Assegid S. Prevalence of hypertension and its risk factors in southwest Ethiopia: a hospital-based cross-sectional survey. Integr Blood Press Control. 2013; 6: 111-117. PubMed: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3753877/
5. Gobezie T, Belay Y. Drug therapy problem among patients with cardiovascular disease in Felege Hiwot referral hospital, NE, Ethiopia. Int J Pharmacy Teaching Practice. 2014; 5: 989-996
6. Katzung BG, Trevor AJ. Basic and clinical pharmacology. United States of America, McGraw-Hill. Chapter 11: antihypertensive agents. 2015; 169-187.
7. Likisa J, Woldu MA, Dinba J. Assessment of drug related problem among hypertensive patients on follow up in adama hospital medical college.    East Ethiopia. 2014; 19: 201-209.
8. Mahmud MA. Drug therapy problems and quality of life in patients with chronic kidney disease. Int J Res Med Sci. 2013; 1: 74-85.
9. Mandavi, D’Cruz S, Sachdev A, Tiwari P. Adverse drug reactions & their risk factors among Indian ambulatory elderly patients. Indian J Med Res. 2012; 136: 404-410. PubMed: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510886/
10. Perterson C. Characterization of drug related problem and associated factors at clinical pharmacy-naïve hospital in northern part of Sweden. 2017. e834a1c612f7469116a649b902ef5674436a.pdf
11. Rosendorff C, Black HR, Cannon CP, Gersh BJ, Gore J, et al. Treatment of hypertension in the prevention and management of ischemic heart disease: a scientific statement from the America Heart Association Council for High Blood Pressure Research and the Councils on Clinical Cardiology and Epidemiology and Prevention. Circulation. 115: 2761-2788. PubMed: https://pubmed.ncbi.nlm.nih.gov/17502569/
12. Redzuan AM, Ramali AR, Pheng MT. Drug related problem hypertensive patients with comomobidities. 2017. 20: 411-419.
13. Trevisol D, Moreira L, Fuchus F, Fuchss: Hrqol Is Worse In Individuals  With Hypertension Under Drug Treatment: Results Of Population Based Study. J H Hyperten. 2003.
14. Van den Bemt PM, de Jong-van den Berg LT. Drug-related problems in hospitalized patients. Drug Safety. 2014; 22: 321-333. PubMed: https://pubmed.ncbi.nlm.nih.gov/10789826/
15. Yone De Almeida. Drug related problems observed in pharmaceutical care service in belo horizonte, Brazil. Bra J Pharmaceut Sci. 45: 2009.