Deep vein thrombosis (DVT) is a major health problem with substantial mortality and morbidity in medically ill patients. Prevention of DVT by risk factor stratification and subsequent antithrombotic prophylaxis in moderate- to severe-risk category patients is the most rational means of reducing morbidity and mortality.

1. Deep vein thrombosis prophylaxis in a tertiary care center:
An observational study

2. Original Article
Deep vein thrombosis prophylaxis in a tertiary care
center: An observational study
Aparna Yerramilli a,
*, Shilpa Katta b
, Supriya Kidambi b
,
Naveen Kumar Kotari b
, Santosh Devulapally b
, Sanjeev Sharma c
a
Associate Professor, Pharm. D Head of the Department, Sri Venkateshwara College of Pharmacy, Affiliated to
Osmania University, Hyderabad 500081, Telangana, India
b
Pharm. D Interns, Sri Venkateshwara College of Pharmacy, Madhapur, Hyderabad, India
c
Clinical Pharmacologist, Apollo Hospitals, Jubilee Hills, Hyderabad, India
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x
a r t i c l e i n f o
Article history:
Received 15 February 2015
Accepted 24 August 2015
Available online xxx
Keywords:
Deep vein thrombosis
Venous thromboembolism
DVT prophylaxis
Risk stratification
Enoxaparin
a b s t r a c t
Background: Deep vein thrombosis (DVT) is a major health problem with substantial mor-
tality and morbidity in medically ill patients. Prevention of DVT by risk factor stratification
and subsequent antithrombotic prophylaxis in moderate- to severe-risk category patients is
the most rational means of reducing morbidity and mortality.
Objective: To study the management strategies for DVT prophylaxis in a tertiary care center
and evaluate the prophylactic dosing patterns for DVT prevention.
Methods: A prospective, observational study was performed in the intensive care units and
medical wards of a tertiary care center. A structured proforma was designed for risk
assessment and stratification of DVT in critically ill patients with recommended thrombo-
prophylaxis. The dosing patterns of all medications given for DVT prophylaxis were ana-
lyzed for their appropriateness according to 8th ACCP guidelines.
Results: A total of 480 patient charts were reviewed. It was observed that 358 patients (74.6%)
were on mixed prophylaxis, 38 patients (18.5%) were on pharmacological prophylaxis, and 33
patients (6.9%) were on mechanical prophylaxis only. Enoxaparin and graduated compres-
sion stockings were the most commonly used pharmacological and mechanical prophylax-
es, respectively. The prophylaxis guidelines were followed in 77% of the study population.
The reasons for inappropriate dosing patterns were found to be subtherapeutic dosing and
overdosing.
Conclusions: Our study revealed that a higher proportion of the patients who are at high risk
are currently given thromboprophylaxis as per the standard prophylactic recommenda-
tions. There is still considerable scope for improvement in the management of DVT in all
units of the institution.
# 2015 Indraprastha Medical Corporation Ltd. Published by Elsevier B.V. All rights
reserved.
* Corresponding author at: Sri Venkateshwara College of Pharmacy, 86, Hitech City Road, Madhapur, Hyderabad 500081, Andhra Pradesh,
India. Tel.: +91 9704231971.
E-mail address: svcppharmd.hod@gmail.com (A. Yerramilli).
APME-317; No. of Pages 5
Please cite this article in press as: Yerramilli A, et al. Deep vein thrombosis prophylaxis in a tertiary care center: An observational study,
Apollo Med. (2015), http://dx.doi.org/10.1016/j.apme.2015.08.002
Available online at www.sciencedirect.com
ScienceDirect
journal homepage: www.elsevier.com/locate/apme
http://dx.doi.org/10.1016/j.apme.2015.08.002
0976-0016/# 2015 Indraprastha Medical Corporation Ltd. Published by Elsevier B.V. All rights reserved.

3. 1. Introduction
Venous thromboembolism (VTE), which includes deep venous
thrombosis (DVT) and pulmonary embolism (PE), is a common
and potentially life-threatening condition in critically ill
patients. Anticoagulant drug therapy is aimed at preventing
pathological clot formation in patients at risk and preventing
clot extension and/or embolization in patients who have
developed thrombosis.1,2
Majority of the studies have been conducted and published
in western countries where DVT is more common, whereas,
there is paucity of data from Indian subcontinent regarding the
incidence of VTE. Some of the recent studies published from
Asian countries have shown that DVT is not a rarity in Asian
patients as was thought earlier.3
The prevailing belief that VTE
in the ASIAN population is less than in the western population
has been disproved by recent studies and there appears no
reason to believe that it is any different in India.5
The incidence of DVT in India as reported is 1% of the adult
population after the age of forty and 15–20% in hospitalized
patients. The risk of DVT is 50% in patients undergoing
orthopedic surgery, particularly involving the hip and knee,
and it is 40% in patients undergoing abdominal or thoracic
surgery. About 1 in 100 who developed DVT can develop PE,
which can be fatal. As per India-specific ENDORSE study data
presented at Geneva, 50% of hospitalized patients in India are
at high risk of developing VTE at any point in time and the
proportion of Indian patients considered at risk for VTE (53.6%)
was similar to that of the global patients at risk for VTE
(51.8%).3,4,6
In developing countries, such as India, a significant
prevalence of etiological risk factors for DVT and prothrom-
botic factors has been shown amongst hospitalized
patients.7
Studies have shown a need of DVT prophylaxis
in 95% of intensive care unit (ICU) patients in India with
significant underuse of prophylaxis in only 55% of the high-
risk patients.8
Another study in the Indian population has
shown an overall incidence of confirmed DVTs to be 17.46
per one lakh patients with 64% being nonsurgical non-
trauma patients.9
Critically ill patients are at increased risk of VTE due to
predisposing comorbid conditions, occurrence of sepsis,
trauma, and postadmission events.10
Individual identification
of suspected DVT cases could be a difficult task and many
cases could be missed. However, blanket prophylaxis of all
admitted patients may not be cost-effective, especially in a
developing country, such as India.11
Thus primary prevention
of VTE with risk assessment and stratification for DVT and
subsequent antithrombotic prophylaxis in moderate- to
severe-risk category patients is the most rational means of
reducing mortality and morbidity.
The need for DVT prophylaxis is usually underestimated.
Only 10% of individuals who require DVT prophylaxis actually
get it; the remaining 90% of individuals are deprived of DVT
prophylaxis because of lack of awareness or skill.12
The 8th conference of American College of Chest Physicians
(ACCP) developed guidelines for the use of low-molecular
weight heparins (LMWHs) and unfractionated heparins (UFH)
in the prevention of VTE in patients with acute illnesses.12
DVT can be prevented by regular physical activity,
especially if an individual is immobilized for longer time.
Mechanical DVT prophylaxis may be considered in all
immobile patients and should be used for those who cannot
receive anticoagulants, such as intermittent pneumatic
compression (IPC) devices, graded compression stockings
(GCS), and venous foot pumps. Pharmacological prophylaxis
includes low-dose unfractionated heparin (LDUH), LMWH,
vitamin K antagonists (most often warfarin), and fondapar-
inux. The guideline recommendations for thromboprophy-
laxis in patients at risk of VTE are given in Appendix.14
However, the use of DVT prophylaxis in hospitalized
medical patients still remains suboptimal, around 15–16%.13
Hence, we sought to study the patient profiles for risk
factors and evaluate the drug dosing patterns for DVT
prophylaxis among medically ill and surgical patients treated
at our institution. This study aims to evaluate the usage of
prophylaxis in our institution.
2. Methods
A single-center, prospective, and observational study was
carried out for six months at Apollo Hospitals, Jubilee Hills,
Hyderabad, which is a 630 bedded tertiary care hospital with 50
superspecialty services in India. Ethical clearance was
obtained from the Institutional Ethics Committee (IEC)
(Protocol No. SVCP/04/2013) before initiating the study.
A structured proforma was designed for risk stratification
of DVT in critically ill patients adapted from Caprini's risk
stratification scorecard. The risk factors for DVT used in this
protocol to stratify patients are similar to that published by
ACCP and the International Union of Angiology (IUAS)
consensus statement and have been used previously for
DVT risk assessment alongside ACCP and IUAS risk score
models in other studies done in developing countries. The risk
assessment and stratification scorecard and data collection
form used are given in Appendix.
All the patient charts were reviewed in the medical and
surgical units and the data of 480 patients who were on DVT
prophylaxis were collected. Individual Risk factor screening
was done to calculate risk factor score, thus categorizing
patients into low, moderate, and high risk.
Demographic data, including patient's age, sex, and body
weight, were collected. Other baseline information like
diagnosis, comorbidities, past medication history, past surgi-
cal history, family history, social history, allergies, any
invasive instrumentation, such as ventilators, venous cathe-
ters, baseline laboratory data (hematological data, coagulation
profile and renal parameters), etc. were also noted down. Renal
data plays a crucial role because as per enoxaparin package
insert dose adjustment is recommended in patients with
severe renal impairment (creatinine clearance <30 mL/min).
Patients were stratified to low-, moderate-, and high-risk
categories. Any prophylaxis given and relevant investigations
for DVT (D-dimer, Doppler ultrasound, high-resolution chest
computed tomography, pulmonary angiography) that was
done was also noted. Assessment of risk of bleeding and
contraindications to thromboprophylaxis was performed. The
current prescribed prophylaxis (mechanical and chemical)
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x2
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4. with dose, frequency, route of administration, date of drug
initiation and stop date, and monitoring parameters were
collected.
Data were analyzed for the risk factor categorization and
appropriateness of thromboprophylaxis compared to the 8th
ACCP guidelines and reported. Descriptive statistical analysis
was performed in calculation of categorical variables.
3. Results
A total of 480 patient charts were reviewed and analyzed. It
was observed that male patients were relatively higher than
female patients. Of the total 480 patients, 58% were medical
patients and 42% were surgical patients. Majority of the study
population receiving thromboprophylaxis were in the age
group of 61–80 years (40.1%) and least in the age group of 81–
100 years (4.6%), with a mean age of 56.7 years and mean BMI
25.3 kg/m2
. The demographic characteristics are shown in
Table 1. An average risk factor range of 3–4 per patient was
observed with top three multiple risk factors being age (82.5%),
obesity (48.1%), and surgery (42%) (Fig. 1). Orthopedic surgery
(45%) was the most common type of surgery among the
surgical patients.
Risk factor screening was done and the patients were
categorized into low (3%), moderate (24%), and high risk (73%)
based on the risk factor scoring (Table 1). It was observed that
93.3% were on pharmacological prophylaxis and 6.7% were on
only mechanical prophylaxis, of which 74.6% were on mixed
prophylaxis, 18.5% were on only pharmacological prophylaxis,
and 6.9% were on only mechanical prophylaxis.
In our study, LMWH (92.7%), with enoxaparin 40 mg, was
the preferred choice of anticoagulant in surgical as well as
medical ward patients, followed by fondaparinux (1%). Among
mechanical prophylaxis available, graduated compression
stockings (68%) were commonly used followed by sequential
compression devices (SCD) (13.3%) (Fig. 2). The most common
contraindications to pharmacological prophylaxis were active
bleeding (4.17%), clinically relevant renal impairment (1.04%),
hepatic impairment (0.63%), and low platelets count (0.63%).
ACCP recommended prophylaxis guidelines were followed
in 77% of the study population, which was significantly higher
compared to global ENDORSE data.
The most common reasons attributed to the inappropriate
thromboprophylaxis were subtherapeutic dosing (15.6%),
overdosing (1.5%), and renal impairment (6%) (Table 2).
4. Discussion
This study explores the use of DVT prophylaxis in a tertiary
care center. Out of 480 patient charts reviewed, majority of our
study population were males, overweight, and above 50 years.
Nearly two-thirds of the study population was in medical
wards and the remaining in surgical units requiring acute care.
Fig. 1 – Patient risk factors for DVT. THR, total hip
replacement; TKR, total knee replacement; COPD, chronic
obstructive pulmonary disease; DVT, deep vein
thrombosis; PE, pulmonary embolism.
Fig. 2 – Management strategies for DVT prophylaxis. GCS,
graded compression stocking; SCD, sequential
compression devices.
Table 1 – Demographic characteristics of the study
population.
Variables Total no of patients, n = 480 (%)
Gender
Males 257 (54%)
Females 223 (46%)
Other characteristics
Mean age (years) 56.7 Æ 15.27
Mean BMI (kg/m2
) 25.3 Æ 4.81
Medical department
Wards 315 (66%)
ICU 165 (34%)
Unit
Medicine 279 (58%)
Surgery 201 (42%)
Comorbidities
Cardiovascular 243 (51%)
Respiratory 35 (7%)
Others 112 (23%)
No comorbidities 90 (19%)
Level of risk
Low (0–1) 14 (3%)
Moderate (2–4) 117 (24%)
High (≥5) 349 (73%)
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x 3
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5. About half of the study population showed cardiovascular
comorbidities followed by other comorbidities. Multiple
system involvement was seen in many patients. Whereas in
a study conducted by Pandey et al., at AIIMS, India, it was
shown that respiratory system involvement was seen in 41.8%
of the patients while cardiovascular system involvement was
seen in only 17.1% of the patients.15
Nearly half of the study population was postsurgical, of
which 75% are at highest risk for DVT. Orthopedic surgery runs
a higher risk for DVT (45%). In addition to surgery, age, obesity,
and immobility were among the most frequently documented
risk factors. Patients at high risk (73% vs. 48.4%) were higher in
our study when compared to TUNE-IN study conducted by
Wessels and Riback.16
Overall prophylaxis in at-risk VTE patients was high (77%)
in our study and as per ACCP recommendations, enoxaparin
40 mg once daily (54.3%) was the most common agent used.
Whereas the Indian data from ENDORSE study revealed that
despite a similar proportion of patients at risk in India and
other participating countries, there was major underutiliza-
tion of prophylaxis (17.4%) in India as compared to higher
usage of prophylaxis globally (50.2%).4,17
Pharmacological prophylaxis in medical and surgical
patients was evaluated for appropriateness. Pharmacological
prophylaxis was commonly used type of prophylaxis (93.1%).
Inappropriate thromboprophylaxis was observed in 111
patients (23%). The most common reasons attributed to the
inappropriate thromboprophylaxis were overdosing due to
overweight or obesity, renal impairment, and subtherapeutic
dosing.
The combination of enoxaparin 20 mg and mechanical
prophylaxis is not appropriate according to the ACCP guide-
lines, hence considered as subtherapeutic dosing. This might
be due to the misconception of some clinicians that the
combination of enoxaparin 20 mg with mechanical prophy-
laxis would be sufficient to reduce the DVT incidence. The
standard dose recommended is enoxaparin 40 mg OD and/or
mechanical prophylaxis in moderate- to high-risk patients.
Studies have not shown significant benefit of mechanical
prophylaxis relative to anticoagulant therapy; however, accord-
ing to CHEST guidelines, mechanical prophylaxis is an accept-
able option in certain patient groups or in combination with
anticoagulant therapy to improve efficacy.11,18
Documented
contraindications (active bleeding, renal impairment, hepatic
impairment, and low platelet counts) were noted in few
patients, who were on only mechanical prophylaxis. Among
mechanical prophylaxis available, graduated compression
stockings were commonly used followed by SCD.
A Point Prevalence study of DVT prophylaxis in the
institution was conducted. Out of 226 patient charts reviewed,
more than half of the study population (120 patients) had a
very high risk for DVT. It was found that 25.6% were on DVT
prophylaxis, which was greater compared to that of Indian
data from ENDORSE study (17.4%).
The study showed that a significant percentage of admis-
sions in medical wards and ICU were subject to very high risk
of DVT. Early recognition of these risk factors and prompt
prophylaxis in high-risk cases can be really effective in
preventing these life-threatening complications. Though,
ACCP has laid down clear guidelines on DVT prophylaxis in
medically ill patients, several studies done in the Western
countries have also shown the underuse of DVT prophylaxis in
hospitalized medical patients.19,20
Overdosing may be due to lack of proper risk factor
screening techniques, practical feasibility, lack of experience
and awareness in healthcare personnel, and poor implemen-
tation of recommended guidelines.
Reasons for underutilization or subtherapeutic dosing of
prophylactic agents include:
Concerns about an increased risk of bleeding from antic-
oagulants.
Lack of clear indications and contraindications for antico-
agulant prophylaxis.
Lack of time to consider DVT prophylaxis in every patient.
Physicians' belief that mixed prophylaxis would be sufficient
to reduce DVT incidence.
Lack of awareness and concerns for cost of DVT prophylaxis
in all critically ill patients could also be an important factor,
particularly in developing countries, such as India.
5. Limitations
All the patients who are at risk of DVT were not considered.
Only those patients on any thromboprophylaxis were studied.
This was a single-center study and the results cannot be
generalized to other medical centers. There was no follow-up
to evaluate the duration of prophylaxis. Another limitation of
the study was that pediatric patients, who were excluded, also
might have been at risk for VTE.
6. Conclusion
The findings of our study showed that a relatively larger
proportion of the patients were currently on prophylaxis as per
standard prophylactic recommendations. The overall rate of
inappropriate thromboprophylaxis was 23%, the most com-
mon reasons being: overdosing and subtherapeutic dosing. A
high rate of appropriateness and increased use of LMWH was
seen in our study population due to frequent awareness
campaigns in hospital. Risk assessment forms are being used
Table 2 – Reasons for inappropriate DVT prophylaxis.
Reasons for inappropriate dosing Medical patients (n = 58) Surgical patients (n = 53) Total patients n = 480 (%)
Overdosing Renal impairment 20 9 29 (6%)
Obesity 6 1 7 (1.5%)
Subtherapeutic dosing 32 43 75 (15.6%)
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x4
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Please cite this article in press as: Yerramilli A, et al. Deep vein thrombosis prophylaxis in a tertiary care center: An observational study,
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6. in some units but need to be followed in more units and
patients.
This study data may be useful to implement DVT risk
stratification strategy in hospitalized patients and improve the
prescribing patterns of prophylaxis where indicated. Success-
ful programs like incorporation of risk assessment and
stratification tools in routine patient work-up and interven-
tions to increase awareness of DVT prophylaxis in health care
professionals need to be implemented in our heath care
system to improve VTE prophylaxis and decrease rates of VTE
and its complications.
Conflicts of interest
The authors have none to declare.
Acknowledgements
We are immensely thankful to Dr Rajib Paul, Internal Medicine
for his guidance and support during the Point Prevalence
study; Apollo Hospitals, Osmania University, Principal Prof.
Prathima Srinivas; and Management of Sri Venkateshwara
College of Pharmacy, for the encouragement and support
provided.
Appendix. Supplementary data
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.apme.2015.08.002.
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APME-317; No. of Pages 5
Please cite this article in press as: Yerramilli A, et al. Deep vein thrombosis prophylaxis in a tertiary care center: An observational study,
Apollo Med. (2015), http://dx.doi.org/10.1016/j.apme.2015.08.002