1.How to Minimize ‘Lost to Follow-up’ in a Cohort Study in Pharmacoepidemiology? :
Eri KAWABE ; Kazuo SAMIZO ; Tsugumichi SATO ; Kiyoshi KUBOTA
Japanese Journal of Pharmacoepidemiology 2007;12(1):1-12
Objective : To find methods to minimize ‘lost to follow-up’ in the long-term follow-up in a pilot study of Prescription-Event Monitoring in Japan (J-PEM) where hypertensive subjects who took losartan or a control drug and gave informed consent to the study were directly followed by researcher for years.
Design : Cohort Study
Methods : We conducted the follow-up survey twice, in which questionnaires were sent to hypertensive patients who had consented to being involved in the survey and returned it by mail. In the questionnaire, we asked about the use of the monitoring drug, change of medical institutions for the treatment of hypertension, significant health-related events. In the second survey, we reminded the non-responders by a letter of reminder and by telephone. When no information was obtained from the subject, we sent a letter, together with a copy of the informed consent given by the subject, to the municipal office where the subject's home was registered to inquire about the subject's current address and related information including the vital status. We calculated Standardized Mortality Ratio (SMR) using the information on death obtained from the mailed questionnaires, telephone and information in the municipal office.
Results : In a pilot study of J-PEM on losartan, 4344 and 3517 questionnaires were sent to pharmacists and doctors, respectively. The doctors handed the informed consent form to the patients and 422 patients agreed to participate the study and sent back the signed form to the study office. In the first and second surveys, a questionnaire was mailed to the subject approximately 1 and 5 years after the first prescription of losartan or a control drug, respectively. The response rate was 73 and 60% in the 1 st and 2 nd survey, respectively. In the manuscript, the results of the 2 nd survey were mainly presented. The reminders by mail and telephone increased the response rate from 60 to 81% and provided the information on the vital status for 86% of the subjects. The response rate was further increased to 84% and the vital status was known for 99% when the information in the municipal office was used. SMR was estimated to be 0.59 (95% CI : 0.34-1.01) before reminding subjects, 0.78 (0.52-1.17) after reminding subjects by a letter and telephone and 0.92 (0.65-1.31) after further addition of the information from the municipal office. During the 5 years of the observation, 21% of 343 subjects who sent back a filled questionnaire did and 70% did not change the clinic/hospital where they received the care for hypertension, while 9% did not answer the relevant question.
Conclusion : The method of the systematic survey may be useful in minimizing the ‘lost to follow-up’ subjects in the long-term pharmacoepidemiology studies in Japan where a patient can change the clinic/hospital for his/her own health care without any letter of reference. In the systematic survey, the researchers may try to follow the subjects by using several methods including reminders like a letter or telephone as well as the use of the information in the municipal office. To facilitate better follow-up, a careful design of the study including the proper design of the informed consent form is essential to maximize the amount and quality of the available information, particularly when the subject has a serious event or dies in a hospital or institution apart from that where the patient has been registered.
2.A 10-Year Study on Antihypertensive Drug Use Based on Prescription Data in Bohsei Pharmacy
Kazuo SAMIZO ; Chikuma HAMADA ; Chiyoji ISHIKURA ; Tadashi KUSUNOKI
Japanese Journal of Pharmacoepidemiology 1996;1(2):107-115
Objective : To examine antihypertensive drug use in major therapeutic categories and to compare with guidelines for antihypertensive therapy.
Design : Cross-sectional drug utilization survey.
Methods : Prescription data on antihypertensives, from 1985 to 1994, were extracted from electronic record accumulated in Bohsei Pharmacy. Repeated prescriptions were identified by patients' identification code. Patients using diuretics (DU), beta-blockers (BB), Ca-channel blockers (CCB), ACE-inhibitors (ACEI), and others were counted in each calender year. These data were compared with 1993 annual utilization data of antihypertensive drugs in Western countries obtained from a commercial database.
Results : The use of CCB and ACEI increased to reach a high proportion of 43.0 % and 18.7 %, respectively, in 1994. On the other hand, the use of DU and BB showed a marked decrease and DU accounted for 16.3 %, BB for 13.5 % in 1994. The other categories were minor. These figures from Bohsei Pharmacy formed a contrast to those in Western countries. For instance, the use of DU waspredominant in the UK. In the US and Germany, CCB was widely used (≅30%) but DU was also used to a similar extent (30-40%).
Conclusion : The pattern of antihypertensive drug use found in the record of Bohsei Pharmacy may be judged to be appropriate since the JNC and other guidelines recommend DU, BB, CCB, and ACEI as the first line drugs. However, the proportion of the use of CCB is an issue of concern and might be criticized to be too high in light of the fact mentioned by those guidelines that efficacy/safety of CCB's has not yet been proven sufficiently based on morbidity and mortality data.
3.Communication Effects of Written Drug Information on Patient Attitude, especially Those of Risk Information
Satomi MUKAIDE ; Yasuo OHHASHI ; Noriaki NAKATANI ; Kazuo SAMIZO
Japanese Journal of Pharmacoepidemiology 1997;2(2):69-80
Objective : To evaluate communication effects of the intervention by written risk information on prescribed drugs and explore the influencing factors.
Design : A randomized prospective controlled trial.
Setting : An outpatient unit in a medical center.
Patients : 243 outpatients prescribed antihypertensive drugs.
Intervention : Patients were randomized into either the study or control group. The study group received sheets showing risk information in addition to drug's name and efficacy while the control group received those without risk information. Patients were requested to complete a questionnaire before and 1 month after receiving information.
Main outcome measures : The communication effects, defined in terms of patient satisfaction, helpfulness of the sheets, reassurance about taking drugs and compliance evaluated by himself.
Results : Of 243 patients, 123 completed the second questionnaire. Of those 123, the study group patients were significantly more satisfied (p=0.035). For other 3 measures, there were no significant differences between the study and control groups. But almost all patients regarded the sheets helpful. After receiving the sheets with or without risk information, 67 (61.5%, 109 answered) were reassured and the compliance was said to be improved with 32 (28.1%, 114 answered).
From the exploratory analysis of 112 patients having completed both questionnaires, patients who evaluated the sheets helpful tended to be more reassured. The compliance of patients who were reassured tended to be better.
Conclusion : Patients regarded the written drug information as a helpful medium and were more satisfied with risk information. Irrespective of whether risk information was included, reassurance and better compliance were attained by the written drug information.
4.The Need to Complement the Information Obtained from Pharmacists in the Community Pharmacy by That in the Hospital Pharmacy in Prescription-Event Monitoring in Japan (J-PEM)
Kazuo SAMIZO ; Shirou HINOTU ; Misako AOYAMA ; Miki YOKOTUKA ; Yasuko MORITA ; Eri KAWABE ; Tsugumichi SATO ; Cikuma HAMADA ; Kiyoshi KUBOTA
Japanese Journal of Pharmacoepidemiology 2000;5(1):11-24
Objective : To evaluate the necessity to complement the information obtained from pharmacists in the community pharmacy by that from the hospital pharmacy in Prescription-Event Monitoring in Japan (J-PEM) by using data in a J-PEM pilot study.
Methods : For each patient, two questionnaires were sent to the prescribing doctor and the pharmacist who registered the patient ID code in the pilot study. If the patient ID code was registered by the pharmacist in the community pharmacy and if a pharmacist inside the hospital where the prescription was issued was willing to co-operate, a third questionnaire for the same patient was sent to the pharmacist in the hospital pharmacy. The information given by pharmacists was analyzed for 150 pairs of questionnaires (on 150 patients) sent back from pharmacists in both community and hospital pharmacies. The questions in the questionnaire were categorized into [1] those on drugs used by patients (concurrent drugs, daily dose of the drug monitored, and compliance), [2] those on events which the patient had experienced after the prescription of the drug monitored, [3] those on patients (the first date of prescription, reason of prescribing the drug monitored, initial date when the disease developed, underlying diseases or complications and whether and when the patient was lost to follow-up). The questionnaires were examined to determine whether the answer was given to each question. When the answer was given, its quality and quantity were then assessed. The answer to each question given by the pharmacist in the community pharmacy (C) and that by the pharmacist in the hospital pharmacy (H) were compared by the McNemar test after the pairs of answers were classified into the following categories : [1] C is better than H, [2] H is better than C, [3] C and H are similar to each other, and [4] impossible to classify. The difference was considered to be significant where p<0.05.
Results and conclusion : For the initial date when the disease developed and 'underlying diseases or complications', H was significantly better than C. However, for concurrent drugs, compliance and events, C was significantly better than H. Otherwise, the difference was not statistically significant. Being compatible with the superiority of C over H in regard to concurrent drugs and events, the fraction of patients lost to follow-up during the observation period was small not only in H but also in C. This observation may be associated with the fact that almost all prescriptions were issued by a single hospital in more than 60% of community pharmacies in the pilot study, and most patients identified in the study were probably a regular visitor to one of such community pharmacies. The most important information to be provided by the pharmacists in J-PEM is that on events and drugs used by patients. It is thought to be not necessary to complement the information obtained from the community pharmacy by that from the hospital pharmacy.