Patient Compliance With Outpatient Prophylaxis: An Observational Study

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1 Patient Compliance With Outpatient Prophylaxis: An Observational Study CLIFFORD W. COLWELL, JR, MD*; PAMELA PULIDO, BSN, RN*; MARY E. HARDWICK, MSN, RN*; BEVERLY A. MORRIS, RN, CNP abstract The need for prophylaxis against venous thromboembolic disease following lower-extremity joint replacement is well documented and accepted. Although low molecular weight heparin is approved for inpatient and extended prophylaxis beyond the hospital environment, orthopedic surgeons must determine the duration of injectable low molecular weight heparin based on the period of venous thromboembolic disease risk and on patient compliance with self-administration of medication at home. Lack of confidence in patients ability to self-administer injections may contribute to hesitancy in prescribing injectable prophylaxis. This observational study evaluated the effectiveness of a self-injection education program. Findings demonstrate that when properly instructed, patients safely and efficaciously self-administer low molecular weight heparin at home. With shorter hospital stays, self-administration of low molecular weight heparin may optimize the clinical outcomes of orthopedic patients. Antithrombotic prophylaxis for the prevention of venous thromboembolic disease following total joint arthroplasty is recommended. Without the use of prophylaxis, thromboembolic complications have been reported in 50% to 80% of patients screened with venography after surgery. 1,2 In contrast, the incidence of clinically symptomatic thromboembolic complications after early prophylaxis of 7 to 10 days has been estimated to be 5%. 3,4 Since 1986, it has been recommended patients undergoing total joint arthroplasty receive prophylaxis for the prevention of venous thromboembolic disease for a minimum of 7 to 10 days. 5 In 1993, a low molecular weight heparin, Lovenox (enoxaparin sodium; Aventis Pharmaceuticals Inc, Bridgewater, NJ), was approved for prophylactic use following total hip replacement, and in 1995, Lovenox received approval for prophylactic use following total knee arthroplasty. Since then, its use has become widespread, and as early as the 1995 ACCP Conference, 7 to 10 days of enoxaparin was recommended as an A1 method of prophylaxis for the prevention of thromboembolism. 6 A study of extended use of enoxaparin 40 mg once a day for an additional 14 days, based on an initial 7 to 10 days of enoxaparin (30 mg every 12 hours), demonstrated the relative risk of thrombosis was reduced by 42% compared with placebo, thereby establishing the efficacy of extended use. 7 In 1998, extended use was approved by the US Food and Drug Administration. 8 With the current hospital stay averaging 4 days, this extended use of enoxaparin has necessitated that patients self-administer injections at home to obtain the benefits of the 7- to 10-day prophylaxis regimen. Orthopedic surgeons face the dilemma of determining the duration of low molecular weight heparin administration based on the period of risk and patients compliance with self-medication after hospital discharge to their home. However, orthopedic surgeons lack of confidence in patients ability to self-administer injections may contribute to hesitancy in prescribing this type of prophylaxis. The lack of confidence in patient compliance is not unfounded. Overall oral medication compliance rates have been reported to range from 10% to 94%. 9 Greenberg 10 reported once-daily and twice-daily medication regimens were associated with significantly better compliance (73% and 70%, respectively) than medication regimens of three times daily (52%) and four times daily (42%). 10 Sackett and Snow 11 found short-term medication treatment had a better compliance From the *Scripps Clinic, La Jolla, Calif, and DePuy Johnson & Johnson, Warsaw, Ind. Reprint requests: Clifford W. Colwell, Jr, MD, Scripps Clinic, N Torrey Pines Rd, MS126, La Jolla, CA FEBRUARY 2005 Volume 28 Number 2 143

2 TABLE 1 Patient Enrollment and Exclusion in the Enoxaparin Self-Injection Study No. Patients screened 70 Patients enrolled 62 Patients excluded prior to study 11 Discharged to skilled nursing facility 5 Surgery cancelled 2 Use of routine anticoagulant 1 Retinal hemorrhage 1 Consent withdrawn 2 Total study participants 51 Patients discontinuing during study 11 Hospital readmission 4 Inability to follow instructions 2 Gastrointestinal bleeding 1 Incision swelling 1 Inconvenience 3 Total completing study (returned diary cards) 40 rate (78%) than long-term treatment (53%). Moreover, an estimated 50% to 90% of patients make unintentional errors when taking medications. 10 The predominant type of noncompliance is dose omissions. 12 Patient compliance with shortterm use of an injectable medication is unknown as a literature search yielded no references on this topic. Patient compliance in home care is a major health issue, with outcomes related to levels of morbidity, mortality, and cost utilization. The most promising strategy to enhance compliance is a combination of interventions including patient education, contracts, self-monitoring, social support, telephone follow-up, and individualized treatment. 13 The majority of patient compliance research focuses on efforts to raise individual compliance; few studies have compliance as the outcome. This study was designed primarily to evaluate individual patients ability to both comply with self-injection and change the dosage and frequency of a regimen during the prescribed treatment period. A secondary goal was to evaluate the effectiveness of a routine self-injection education program to increase orthopedic surgeons confidence in patients ability to self-administer injections. MATERIALS AND METHODS Population Patients who were scheduled for primary or revision elective total hip and knee arthroplasty were prospectively and sequentially recruited into the study. Patients who were willing to participate in therapy and phone interviews for 21 days after surgery gave written consent. Patients with mental or physical limitations to selfadminister injections or planned discharge to other care facilities were excluded. Therapy consisted of postoperative antithrombotic prophylaxis using subcutaneous enoxaparin to prevent venous thromboembolic complications. Patients enrolled in the study agreed to complete the therapy of enoxaparin, participate in 3 follow-up phone interviews with an independent pharmacist, complete self-report injection diaries, and return the diaries to the agency collecting the data. Study Design This observational open-label investigation was conducted at Scripps Clinic in La Jolla, California, using routine enoxaparin patient education. The study was approved by the institutional review board. At a preoperative education class, a clinical nurse discussed enoxaparin, the rationale for its use, and the method of administration. Treatment with 30 mg of enoxaparin every 12 hours began in the hospital on the first postoperative day and continued throughout the hospital stay. Hospital staff nurses began the selfinjection education process with the first injection and continued patient education throughout patients hospital stay. As part of the education, a staff nurse explained the purpose of low molecular weight heparin therapy, demonstrated the subcutaneous injection, and discussed the patient s responsibilities following discharge from the hospital. After instruction, with a staff nurse observing, patients (or a family member designated to administer the injections), demonstrated their injection technique. At that time, the nurse reviewed dosage and regimen schedules with the patients. Patients also were given a take-home selfinjection kit that included an instructional video developed by the manufacturer and written instructional materials outlining the subcutaneous injection technique and potential side effects. On discharge from the hospital, the study coordinator provided a complete supply of syringes prefilled with enoxaparin. Written instructions indicated 30 mg of enoxaparin were to be administered subcutaneously at 9:00 AM and 9:00 PM from postoperative days 1 to 7 and then 40 mg were to be administered subcutaneously at 9:00 AM daily from postoperative days 8 to 21. This regimen followed the same 21-day protocol outlined in a previous study, which reported a 41% risk reduction of thrombosis compared with placebo after 7 to 10 days of treatment. 7 Patients also were given diary cards to complete regarding injection compliance. Demographics and a checklist assessing the education received were obtained from the patients at discharge and were sent to trained pharmacists for independent third-party data collection. Measurement of Compliance Compliance was measured by indirect detection methods consisting of phone interviews by an independent pharmacist and completion of subjective diaries by each participant. Calls were placed on 3 separate occasions (days 5, 13, and 21), throughout the 21-day enoxaparin therapy, with a consistent script read to patients at each call. The pharmacist documented the answers to the questions in the script. Data from the phone interviews and patient diaries were used to determine outcomes. Only returned patient diary cards were used to determine complete or partial compliance. Assessment of enoxaparin usage infor- 144 ORTHOPEDICS

3 PATIENT COMPLIANCE COLWELL ET AL TABLE 2 Patient Demographics of Enoxaparin Self-Injection Study (N=51) Demographic No. (%) Gender Women 27 (53) Men 24 (47) Joint Hip 30 (59) Knee 21 (41) Type of surgery Primary 45 (88) Revision 6 (12) Ethnicity White 49 (96) Hispanic 2 (4) Body mass index Mean Women 26.6 Men 26.7 Age (years) Mean 68.4 Range Length of hospital stay (days) Mean 3.4 Range 2-5 mation received by patients prior to hospital discharge for home therapy was ascertained by a discharge questionnaire and questions to patients during the first phone call. Instruction on completion of the diary cards also was reviewed with patients during the first phone call. The second phone call assessed the success of the change in dosage from 30 mg every 12 hours to 40 mg once daily. Finally, the third call gathered a global assessment of the medication therapy and concluded with a reminder to return the diary cards by mail. RESULTS Of 70 patients screened to participate, a total of 62 patients were prospectively enrolled in the study. Of these, 11 patients were excluded: 5 patients were discharged to a skilled nursing facility, 2 patients cancelled their surgery, 1 was discovered to use routine anticoagulants, 1 had a retinal hemorrhage before surgery, and 2 withdrew their consent. This left 51 patients TABLE 3 Patient Compliance in the Enoxaparin Self-Injection Study Based on Returned Diary Cards (N=51) No. (%) Assessable for compliance 40 (78.4) Overall compliance (partial and complete) 37 (92.5) Complete compliance* 22 (55) Partial compliance 15 (37.5) Noncompliance 3 (7.5) *Defined as 7 days of 30 mg every 12 hours followed by 14 days of 40 mg once daily with all doses given within 1 hour of scheduled administration time. Defined as at least 6 days of 30 mg every 12 hours followed by at least 13 days of 40 mg once a day, and all doses given within 2 hours. Defined as <6 days of 30 mg every 12 hours or <13 days of 40 mg once a day. participating in the study (Table 1). Twenty-seven (53%) patients were women and 24 (47%) patients were men. Mean patient age was 68 years (range: years). Thirty (59%) patients underwent hip arthroplasty and 21 (41%) underwent knee arthroplasty. Forty-five (88%) were primary arthroplasties and 6 (12%) were revision arthroplasties. Mean length of hospital stay was 3.4 days (range: 2-5 days) (Table 2). Of the 51 patients enrolled, 7 (14%) reported a family member or friend gave them the injections. Forty (78%) patients reported completing both enoxaparin regimens by returning diary cards. Eleven patients discontinued study participation during the 40-mg once-daily regimen (Table 1). Four of the 11 patients were readmitted to the hospital before completion. Two of these patients were readmitted for hip dislocation and underwent surgical cup revision; neither patient experienced any unusual bleeding at the surgical site. One patient experienced a dislocation and underwent a closed reduction with incision and drainage of a wound hematoma. One patient was admitted for a partial bowel obstruction, which resolved. Of the remaining seven patients who discontinued study participation, one patient was withdrawn by the physician due to swelling unrelated to bleeding at the incision site. One patient with a history of colitis discontinued the enoxaparin 40 mg after 11 doses because of the presence of blood in the stools. Two patients were discontinued by their physicians after each patient took 40 mg every 12 hours for 6 days without any adverse events. Three patients withdrew from the study citing inconvenience of medication. Compliance Forty (78%) of 51 patients were considered evaluable based on the completion of the medication regimen and the return of completed diary cards. Of these 40 evaluable patients, a total of 37 (92%) were compliant, including partial and complete compliance. Complete compliance, defined as 7 days of 30 mg every 12 hours, followed by a regimen of 40 mg once daily for 14 days, with all doses given within 1 hour of the scheduled administration time, was achieved by 22 (55%) patients. Partial compliance, defined as at least 6 days of 30 mg every 12 hours, followed by at least 13 days of 40 mg once daily, with all doses given within 2 hours of scheduled administration time, was achieved by 15 (37%) patients. The remaining 3 (7%) patients were considered noncompliant, which was defined as 6 days of 30 mg twice daily or 13 days of 40 mg once daily (Table 3). Two of the noncompliant patients were unable to follow instructions and used 40 mg of enoxaparin every 12 hours after discharge; one patient stated she did not receive the 30-mg syringes at discharge, and the second patient did not understand the instructions, although written direc- FEBRUARY 2005 Volume 28 Number 2 145

4 TABLE 4 Patient Education Program Assessment for the Enoxaparin Self-Injection Study (N=50)* No. (%) Received a complimentary 50 (100) enoxaparin injection kit Watched the video about 14 (28) enoxaparin Understood why it was 49 (98) important to self-administer enoxaparin injections Taught how and where to 49 (98) give self-injections Practiced giving self- 35 (70) injections with a healthcare professional observing Comfortable giving self- 34 (68) injections Knew when to give 50 (100) 30-mg dose Knew when to give 49 (98) 40-mg dose *Checklist not received from one patient. tions were sent home with both patients. Neither of these patients experienced any bleeding or adverse events. Outcomes Safety issues involved one patient with a history of colitis with blood in the stools at day 11 of treatment that cleared within 2 days after discontinuation of enoxaparin and one patient with a wound hematoma after dislocation and closed reduction. Sixteen patients reported burning or stinging at the injection site, and one patient reported bruising at the injection site. All of these adverse events were reported as mild. None of the patients experienced any clinical thromboembolic events. At the end of the routine education program provided by the hospital nurses, completed checklists were received from 50 of the 51 evaluable patients. Of these 50 patients, 49 (98%) reported understanding why it was important to self-administer enoxaparin, and were taught how and where to administer the injections. Only 14 (28%) patients reported viewing the video that was provided. Thirty-five (70%) TABLE 5 Subjective Patient Information for the Enoxaparin Self-Injection Study (N=51) Question No. Mean Range During Week 2 of Therapy How are you doing on your enoxaparin medication? (1=poor, 10=excellent) During Week 3 of Therapy How are you doing on your enoxaparin medication? (1=poor, 10=excellent) Do you feel you received enough information on how to give your medication? (1=no information, Do you feel you received enough information on when to give your medication? (1=no information, Was the syringe easy for you to use? (1=very easy, =very difficult) After Completion of Therapy Do you feel you received the proper information on how to give your medication? (1=no information, Do you feel you received enough information on when to give your medication? (1=no information, Was the syringe easy for you to use? (1=very difficult, =very easy) patients reported practicing self-injections with a staff nurse observing, and 38 (76%) said they were comfortable giving the selfinjections. At hospital discharge, 100% of the patients reported knowing when to administer enoxaparin 30 mg, and 49 (98%) reported knowing when to administer the 40-mg injections (Table 4). At the end of the first week of therapy, all patients stated they understood the medication information provided at discharge and knew the reason for using the medication. Twenty-one (42%) of 50 reported they reviewed the discharge information. During the follow-up phone calls, patients were asked to describe their perception of certain aspects of therapy using a 10-point scale (Table 5). Regarding how well patients perceived they were doing with the enoxaparin injections, with 1 being poor and 10 being excellent, the mean response was 8.7 for 48 patients during the second week and 8.9 for 43 patients during the third week. During the third-week interview, regarding whether patients had patients received enough information on how to administer their medication, the mean response was 9.2 (1=no information and. Regarding whether they had received enough information on when to administer their medication, the mean response was 9.4 (1=no information and. Regarding whether the syringe was easy to use, the mean response was 2.3 (1=very easy and 10=very difficult) (Table 5) After the completion of therapy, 36 patients again responded in a returned questionnaire using a scale of 1 to 10 (1=no information and, as to whether they had received enough information on how (mean: 8.8, range: 1-10) and when (mean: 8.9, range: 1-10) to administer the medication. The mean response as to whether the syringe was easy to use was 8.8 (range: 1-10, with 1=very difficult and 10=very easy). Of the 42 patients who returned the final questionnaire, 100% stated they received an explanation of why the medication was necessary and instructions on 146 ORTHOPEDICS

5 PATIENT COMPLIANCE COLWELL ET AL how to administer the medication. Forty (95%) reported they felt they could administer the self-injection at discharge. DISCUSSION Developing a supportive, nonjudgmental, and positive relationship with patients serves to motivate them to comply with a prescribed regimen. 14 A regimen that is simple and easy to follow also facilitates compliance. 15 According to Wixted et al, 16 routine assessment of clinical outcomes with regular feedback allows surgeons to objectively monitor their practice patterns and has the potential to improve patient care. The goal of this study was to assess patient compliance with a prophylactic medication protocol that included a change of both dose and administration times. By phone interview, 50 (98%) of 51 reported completing the initial therapy, but only 41 (80%) of 51 reported completing the second part of therapy. Overall compliance rate, including complete and partial compliance, was 92%, indicating patients can complete the prophylactic therapy. A second goal of the study was to assess the education patients received about the medication and self-injection. Ninety-eight percent of the patients reported knowing the reason for selfadministration of enoxaparin and when to administer the 40-mg dose. Forty-two percent reviewed the information at home after discharge, indicating the value of providing information in written and video formats. These findings and the overall compliance rate indicate the education program provided by the nursing staff was successful at explaining the reason for therapy and providing information in a format patients understood. The only difference between the study patient cohort and the normal patient cohort was the follow-up conducted by telephone. This study cannot document compliance would be the same if there were no follow-up; however, compliance could not be evaluated without some type of followup. Although this study is relatively small with both phone calls and diaries for evaluation of compliance, it is compatible with other studies of compliance. This study does not imply that every patient cohort will respond with similar numbers or what the numbers would be if there were no follow-up. With earlier and earlier discharge from the hospital and increasing recommendations for care outside of the hospital, by necessity, patients will need to take more responsibility for all types of medications following discharge. This study links two different doses and dosing schedules with drug compliance following hospital discharge. When appropriately instructed and monitored, many patients can safely and efficaciously self-administer enoxaparin in the home setting, optimizing the benefits of this medical intervention and the goal of decreasing thromboembolic complications following total joint arthroplasty. REFERENCES 1. Geerts WH, Heit JA, Clagett GP, et al. Prevention of venous thromboembolism. Chest. 2001; 119 (suppl):132s-175s. 2. Lotke PA, Ecker ML, Alavi A, Berkowitz H. Indications for the treatment of deep venous thrombosis following total knee replacement. J Bone Joint Surg Am. 1984; 66: Planes A, Vochelle N, Darmon JY, et al. Risk of deep-venous thrombosis after hospital discharge in patients having undergone total hip replacement: double-blind randomised comparison of enoxaparin versus placebo. Lancet. 1996; 348: Colwell CW Jr, Spiro TE. Efficacy and safety of enoxaparin to prevent deep vein thrombosis after hip arthroplasty. 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Diabetes Care. 1997; 20: Miller NH, Hill M, Kottke T, Ockene IS. The multilevel compliance challenge: recommendations for a call to action. A statement for healthcare professionals. Circulation. 1997; 95: Currie BF, Renner JH. Patient education. Developing a health care partnership. Postgrad Med. 1975; 65: , Padrick KP. Compliance: myth and motivators. Top Clin Nurs. 1986; 5: Wixted JJ, Grover NK, Anderson FA Jr, Fitzgerald RH Jr. Clinical outcomes in orthopaedic surgery. The collaborative efforts of orthopaedic surgeons with industry. Bull Hosp Jt Dis. 1999; 58: FEBRUARY 2005 Volume 28 Number 2 147