Optimizing Warfarin Therapy in a Rural Hospital Through the Use of a Diagnostic Management Team

Eddie Salazar; Christopher Zahner; James Randall Lee; Sanam Koirala

doi:10.29074/ascls.2021003167

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Figure 1.
Warfarin management workflow at the Hamilton General Hospital. DMT, diagnostic management team; EMR, electronic medical record; INR, international normalized ratio; LIS, laboratory information system; PT, prothrombin time; UTMB COAG DMT, University of Texas Medical Branch anticoagulation DMT.
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Figure 2.
The diagnostic management team report for warfarin management.
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Figure 3.
Algorithm for the management of patients with an INR goal of 2–3. INR, international normalized ratio; po, orally; prn, as needed; RTC, return to clinic. Retrieved from https://journal.chestnet.org/article/S0012-3692(12)60122-6/fulltext.
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Figure 4.
Algorithm for the management of patients with an INR goal of 2.5–3.5. INR, international normalized ratio; po, orally; prn, as needed; RTC, return to clinic. Retrieved from https://journal.chestnet.org/article/S0012-3692(12)60122-6/fulltext.
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Figure 5.
Warfarin dose instruction card. DOB, date of birth; INR, international normalized ratio. Adapted from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025075/.
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Figure 6.
Percentage of INR outside of therapeutic range as determined by the fraction of INRs method (calculated by dividing the number of INRs within the range for all patients by the total number of INRs during the selected time interval).²² Percentage calculations for INR <1.5 and INR >4.5 are based on the total number of INRs before and after DMT implementation. DMT, diagnostic management team; INR, international normalized ratio.

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Table 1.

Patient assessment questions incorporated within the diagnostic management team workflow

Verify patient dose:

Missed doses: {YES/NO}

Medication changes: {YES/NO}

Diet or alcohol changes: {YES/NO}

Abnormal bleeding or bruising: {YES/NO}

• Nose
• Sputum
• Emesis
• Urine
• Stool
• Bruising

Falls or injuries: {YES/NO}

Upcoming surgery or procedure: {YES/NO}

Change in medical condition or diagnosis: {YES/NO}

Adapted from https://www.amjmed.com/article/S0002-9343(16)31066-X/pdf.

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Table 2.

Patient characteristics

Patient Characteristics	Total	Percentage
Age group (years)
<60	8	16
61–70	7	14
71–80	18	36
80+	17	34
Sex
Male	24	48
Female	26	52
INR target range
2–3	46	92
2.5–3.5	4	8
Warfarin indications
A-fib	24	48
DVT	14	28
DVT/PE	3	6
PE	4	8
A-Fib/DVT	1	2
Aortic valve replacement	4	8
Total patients	50	100

Totals for age, INR goal, and indications include both males and females.

Abbreviations: A-fib, atrial fibrillation; DVT, deep vein thrombosis; INR, international normalized ratio; PE, pulmonary embolism.

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Table 3.
Time in therapeutic range calculated using the fraction of INRs method
Time of Assessment Target Therapeutic
Range (2–3 or 2.5–3.5) Expanded Therapeutic
Range (±0.2 INR units) Expanded Therapeutic
Range (±0.3 INR units)
Pre-DMT 52.19 63.90 68.78
Post-DMT 63.56 77.33 81.38
Time in the therapeutic range was calculated by the fraction of INRs method, dividing the number of INRs within the target range for all patients by the total number of INRs for all patients during the selected time interval.²² Cutoff values for the expanded therapeutic range (±0.2 INR units) were 1.8–3.2 for an INR goal of 2–3 and 2.3–3.7 for an INR goal of 2.5–3.5.³ Cutoff values for the expanded therapeutic range (±0.3 INR units) were 1.7–3.3 for an INR goal of 2–3 and 2.2–3.8 for an INR goal of 2.5–3.5.²⁵ Abbreviations: DMT, diagnostic management team; INR, international normalized ratio.

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Table 4.

Average percentage of therapeutic INRs before and after diagnostic management implementation

Therapeutic Range	Average % of Therapeutic INRs Pre-DMT	Average % of Therapeutic INRs Post-DMT	t Value	df	Sig. (2-Tailed) P < .05
Target therapeutic range (2–3) or (2.5–3.5)	61.99	73.58	−2.24	49	.030
Expanded therapeutic (±0.2 INR units)	72.07	83.78	−2.73	49	.009
Expanded therapeutic (±0.3 INR units)	75.55	86.2	−2.74	49	.009

Paired-sample t tests were used to test the hypothesis using SPSS version 22. There was a statistically significant increase in the average percentage of therapeutic INRs for both the target and expanded therapeutic ranges (±0.2 and ±0.3 INR units). Cutoff values for the expanded therapeutic range (±0.2 INR units) were 1.8–3.2 for an INR goal of 2–3 and 2.3–3.7 for an INR goal of 2.5–3.5.³ Cutoff values for the expanded therapeutic range (±0.3 INR units) were 1.7–3.3 for an INR goal of 2–3 and 2.2–3.8 for an INR goal of 2.5–3.5.²⁵ Abbreviations: df, degrees of freedom; DMT, diagnostic management team; INR, international normalized ratio.

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Table 5.

Number of therapeutic INRs in the target and expanded therapeutic ranges

Therapeutic Range	No. of Therapeutic INRs Pre-DMT	No. of Therapeutic INRs Post-DMT	t Value	df	P Value (2-Tailed)
Target therapeutic range (2–3) or (2.5–3.5)	107	157	−3.796	49	<.001
Expanded therapeutic (±0.2 INR units)	131	191	−3.866	49	<.001
Expanded therapeutic (±0.3 INR units)	141	201	−3.588	49	.001

Data were analyzed with paired-sample t tests using SPSS version 22. Cutoff values for the expanded therapeutic range (±0.2 INR units) were 1.8–3.2 for an INR goal of 2–3 and 2.3–3.7 for an INR goal of 2.5–3.5.³ Cutoff values for the expanded therapeutic range (±0.3 INR units) were 1.7–3.3 for an INR goal of 2–3 and 2.2–3.8 for an INR goal of 2.5–3.5.²⁵ Abbreviations: df, degrees of freedom; DMT, diagnostic management team; INR, international normalized ratio; no., number.