Indian J Pharm Sci. 2013 Jan;75(1):53-9.

Study on Impact of Clinical Pharmacist’s Interventions in the Optimal Use of Oral Anticoagulants in Stroke Patients.

Lakshmi R, James E, Kirthivasan R.

Department of Pharmacy Practice, Amrita School of Pharmacy, Amrita Vishwa Vidyapeetham University, AIMS Health Sciences Campus, Kochi-682 041, India.

 

Abstract

Anticoagulants are very useful medications but can also lead to haemorrhagic as well as thromboembolic complications when not used correctly or without proper medical attention. Anticoagulant’s complex pharmacology and pharmacokinetics contribute to its narrow margin of safety. Pharmacist’s unique knowledge of pharmacology, pharmacokinetics and interactions makes them well-suited to assist patients in maintaining safe and effective anticoagulation. Successful anticoagulation therapy implies fewer incidences of therapeutic failures and bleeding complications. The anticoagulation management service staffed by clinical pharmacists is a service established to monitor and manage oral and parenteral anticoagulants. In this research work, 40 patients each were included in the intervention and the control groups. In the intervention group, patient’s knowledge score on anticoagulation increased from an average of 5.6±3.2 to 13.8±0.94 (P=0.000) after clinical pharmacist’s counselling, whereas in the control group there was no significant improvement in patient’s baseline knowledge over the knowledge score at the end of the study (8.0±1.59 vs. 8.3±2.6) (P=0.218). In the intervention group, 73.45% of the international normalised ratio test results were within the therapeutic range, 8.45% supratherapeutic and 18.5% subtherapeutic during the 6 months data collection period. The corresponding data for the control group were 53.2 (P=0.000), 18.4 (P=0.000) and 28.4% (P=0.002), respectively. Forty four adverse drug reactions (ADRs) related to anticoagulants were identified in the intervention group as compared to 56 in the control group. These results revealed that the clinical pharmacist’s involvement in the anticoagulation management improved the therapeutic outcome of patients and demonstrate the benefits of clinical pharmacist guided anticoagulation clinics in India.

KEYWORDS: Anticoagulation management in India, clinical pharmacist, international normalised ratio, thromboembolism, warfarin

PMID: 23901161

 

INTRODUCTION:

Standard oral anticoagulation treatment consists of vitamin K antagonists including warfarin, phenindione and acenocoumarol. Anticoagulation is a high risk treatment, which commonly leads to adverse drug events due to the complexity of dosing these medications, monitoring their effects, and ensuring patient compliance with outpatient therapy.  Their use is limited due to narrow therapeutic index, drug and food interactions, risk of bleeding and need for regular INR monitoring.1 Because of the intensity of the management required, anticoagulation clinics were developed to help physicians manage these patients, keeping a focus on the narrow therapeutic range required to minimize adverse events. 2,3 Patient’s knowledge, awareness of anticoagulants and medication adherence are important factors in achieving good clinical outcome. It has been shown that educational programs are effective to improve the overall clinical situation, but there are a few studies about this subject in developing countries. This work evaluated the clinical pharmacist’s role in improving anticoagulation related therapeutic outcomes.4,5  During the course of anticoagulation therapy, a variety of health care professionals are involved in patient care. The pharmacist’s role is multifaceted and can include monitoring, dosing and provision of drug therapy, patient education, drug interaction screening and research. However, it is important to also recognize the impact of other health care professionals. In stroke patients the anticoagulants are prescribed for the secondary prevention of stroke for patients with cardiac risk factors like atrial fibrillation, valve replacement etc.

OBJECTIVES:

  • To assess the patient’s baseline knowledge on oral anticoagulation therapy and to make interventions if needed.
  • To monitor and to reduce the occurrence of Adverse Drug Reactions (ADRs) with oral anticoagulants.
  • To study the achievement of goal INR levels.
  • To identify and prevent potential interactions of oral anticoagulants.

EXPERIMENTAL METHODS:

Design of study: Prospective, Interventional study.

Duration of the study: Data collection was done for a period of 6 months from 1st February 2011 to 31st July 2011.

Settings: The study was carried out at the department of stroke medicine and the department of cardiology of Amrita Institute of Medical Sciences (AIMS), Kochi, Kerala, India.

Study sample: Intervention group consisted of all the 40 patients admitted to the department of stroke medicine during the study period and the control group consisted of randomly selected 40 patients admitted to the cardiology ward during the same study period. All the patients satisfied the inclusion and exclusion criteria.

Inclusion criteria:

  1. Patients prescribed oral anticoagulants.
  2. Patients of age ≥ 18 years.
  3. Patients and/or their caregivers (with informed consent) willing to participate in the study.
  4. Patients who are able to read and speak English or the local language Malayalam.

Exclusion criteria:

  1. Patients not on oral anticoagulants. or
  2. Pregnant patients. or
  3. Patients with severe renal insufficiency. or
  4. Patients with active liver disease. or
  5. Patients having visual or hearing impairment.

RESULTS AND DISCUSSION:

Summary of baseline characteristics of the study patients.

Characteristics

Intervention   group (n=40)

Control   group (n=40)

Total No. of patients

40

40

Male

26

26

Female

14

14

Mean age ± SD of male patients(years)

58.35   ± 11.64

56.28   ± 12.84

Mean age ± SD of female patients(years)

51.5   ± 11.61

55.47   ± 14.02

Patients with age >60 yrs

18

15

Patients with no co-morbidity

10

8

Patients with    ≥1   co-morbidity

30

32

Baseline knowledge of patients on oral   anticoagulation (score)

5.0   ± 1.59

8.0   ±2.19

% of patients with goal INR of 2.0-3.0

77.5

82.5

% of patients with goal INR of 2.5-3.5

22.5

17.5

Ethnicity

Asian

Asian

In this research work 40 patients were included in the study group. The male-female ratio was 1.5:1. The mean age of the patients in study group was 55.98 ± 13.47 years(range 30 to 87 years).

INDICATIONS FOR ANTICOAGULATION

Indications for anticoagulation in the study patients.

Indications

Intervention Group (n=40)

[No. (%)of Patients]

Control Group(n=40)

[No. (%)of Patients]

Mitral Valve Replacement(MVR)

9(22.5%)

7(17.5%)

Atrial Fibrillation(AF)

13(32.5%)

32(80%)

Deep vein thrombosis(DVT)

2*(5%)

0

Pulmonary embolism(PE)

2*(5%)

0

Valvotomy

1(2.5%)

0

Bioprosthetic Valve

1(2.5%)

1(2.5%)

Other cardiac risk factors

12(30%)

0

*Patients who developed DVT/PE after an attack of stroke.

Above table depict the various indications for anticoagulation in patients of the intervention and control groups. During the study period the  most common indications for anticoagulation was atrial fibrillation followed by mitral valve replacement. Anticoagulants were also prescribed for secondary prevention in stroke patients who had cardiac risk factors.

ADVERSE DRUG REACTIONS: In study group 44 ADRs were observed and 3of them were

major bleeding events. Minor bleeding events, GI discomfort and skin rashes were also observed.

DRUG & FOOD INTERACTIONS: In the study group, 18 drug interactions were observed and resolved, out of which 10 were drug-food interactions. Two interactions with OTC medications (Ibuprofen) were also observed.

WARFARIN RESISTANCE: During the study period, 2 cases of warfarin resistance were identified and resolved by changing the drug to acinocoumarol.

KNOWLEDGE ASSESSMENT OF PATIENTS ON ORAL ANTICOAGULATION

Patient’s baseline knowledge was assessed by means of a validated questionnaire (Appendix-II) and the mean score was found to be 5.0 ± 2.19. After patient counseling the mean score increased to 13.8±0.9. Hence it is evident that patient’s knowledge on oral anticoagulation improved after counseling by a clinical pharmacist in the intervention group. Baseline knowledge of the patients in the control group regarding oral anticoagulation was also assessed using the same questionnaire and the score was estimated to be 8.0 ± 1.59.

 

Evaluation of patient’s knowledge on oral anticoagulation.

Study groups (n=40)

Patient knowledge score

Baseline

After   intervention

Intervention   group

5.0 ± 2.19

13.8  ± 0.87

Control   group

8.0 ± 1.59

No intervention done

 

ASSESSMENT OF PATIENT SATISFACTION

Assessment of patient satisfaction with the anticoagulation service was done using a questionnaire (Appendix-III).The results show that all the patients were satisfied with the service.

Assessment the patient satisfaction with the pharmacist managed anticoagulation service.

Sl No

Question

Response (n=40)

Yes

No

1

Are you satisfied   with the follow-up arrangements by the anticoagulation management service?

40

0

2

Did you find any   problems associated with the follow-up arrangements?

2

38

3

Are you satisfied   with the counseling provided by the clinical pharmacist?

40

0

4

Were the written   information booklet provided easy to read and understand?

40

0

5

Overall, are you   satisfied with the clinical pharmacist’s involvement in the   management of your anticoagulation   therapy?

40

0

 

SUMMARY OF RESULTS

Parameters

Intervention   group

(n=40)

Control group

(n=40)

P value

No of patients

40

40

Total no. of INR   checks

385

314

0.098

INRs within target   range

77.4%

46.5%

0.000

INRs above target   range

8.31%

23.56%

0.000

INRs below target   range

14.29%

29.30%

0.002

INRs >5

1.56%

6.05%

0.001

INRs >8

0

0.96%

0.079

Fraction of INRs   within therapeutic range

0.774

0.465

ADRs

44

56

Drug interactions   identified

18

8

Warfarin resistance   identified

2

0

No. of patients who   suffered a stroke during oral anticoagulation treatment

1

5

Patient knowledge   score – baseline

5.0

8.0

0.078

Patient knowledge   score –after intervention

13.8

 

Clinical pharmacist’s intervention with respect to increasing patient knowledge on oral anticoagulation helped in maintaining goal INR in the therapeutic range and resulted in better clinical outcomes in the intervention group. Patients receiving oral anticoagulants in control group suffered significantly higher number of strokes as compared to intervention group. More ADRs in the control group and significantly more potential drug interactions in the intervention group were identified.

CONCLUSION:

This study shows that the knowledge of patients regarding oral anticoagulation therapy was insufficient before the clinical pharmacist’s involvement. Improved patient knowledge helped in avoiding potential food interactions and helped in timely monitoring of INRs and led to the achievement of target INR levels. Involvement of a clinical pharmacist can identify potential drug interactions and hence reduce adverse effects. Thus a clinical pharmacist driven anticoagulation service may empower patients to achieve better therapeutic outcome with improved safety.

REFERENCES

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