Subject recruitment, retention, and compliance in clinical trials in periodontics

Recruitment strategies at the Iowa site for parent/infant pairs in a longitudinal dental caries study

BACKGROUND/AIMS

Recruitment of parent/infant pairs can be more difficult and challenging than recruitment of adult subjects alone as the parent has to consider themselves along with the infant to be study participants. In order to determine which recruitment methods most effectively resulted in accrual of subjects, recruitment efforts at the University of Iowa were evaluated, one of three clinical sites involved in a longitudinal prospective study of dental caries.

METHODS

Enrollment goals were 300 parent/infant pairs within a year. Recruitment strategies included (1) a direct mailing to potential subjects who were University of Iowa Hospitals and Clinics patients and potentially met inclusion criteria; (2) face-to-face recruitment visits at medical offices; (3) provision of recruitment materials to staff at off-campus agencies and medical offices serving low-income individuals; (4) a campus-wide mass e-mail; (5) recruitment materials to daycare centers and neighborhood centers; and (6) recruitment at a children's museum.

RESULTS

From these recruitment efforts, 515 potential participants expressed interest and were screened for this study and 348 (68%) were enrolled during an 11-month time period. The face-to-face strategy had the highest recruitment rate of 25%, followed by direct individual mailings at 9% and follow-up telephone calls at 7%. For the face-to-face strategy, the contact at the children's museum was most successful compared to the other office settings. The lowest rate of recruitment of 0.09% was attained with the mass e-mail. However, in terms of actual numbers recruited, the mass e-mail remained an important modality since it yielded 21 recruits and was much less time-intensive.

CONCLUSION

An intensive, multi-pronged recruitment strategy proved successful in meeting enrollment goals and resulted in finishing the enrollment prior to the projected study deadline. Effective recruitment approaches are imperative for a study's success and each recruitment strategy needs to be budgeted and planned for in a study. Investigators may need to adapt their approach to attain the needed number of subjects. Planning needs to include the numbers needed to be approached to attain your recruitment goal, how you will recruit, who will be responsible, and the costs and time commitment for various strategies.

An evaluation of recruitment methods utilized for a clinical trial with periodontal and diabetes enrollment criteria: the Diabetes and Periodontal Therapy Trial

BACKGROUND

Diabetes and its complications are a major United States public health concern.

METHODS

The Diabetes and Periodontal Therapy Trial (DPTT) evaluated whether non-surgical treatment of periodontal disease influenced diabetes management among persons with Type 2 diabetes and periodontitis. The aim of this study was to evaluate DPTT's many recruitment strategies in terms of enrollment success.

RESULTS/CONCLUSION

Targeted recruitment strategies were more effective in identifying individuals who met periodontal and diabetes eligibility criteria. Individuals eligible for a baseline visit/enrollment were more often male, had a younger age at diabetes diagnosis, a longer diabetes duration, more often Hispanic and less often African-American. Tracking and evaluating recruitment sources during study enrollment optimized recruitment methods to enroll a diverse participant population based upon gender, race and ethnicity.

Design, Operation, and Interpretation of Clinical Trials

Randomized controlled clinical trials offer the best evidence for changing clinical practice and informing public health policy. Using examples from the literature, this paper reviews clinical trials for those who may be unfamiliar with their design, operation, and interpretation. In the design of a clinical trial, the question to be answered and a clinically meaningful outcome must be clearly defined. Ethics must be considered, sample size carefully estimated, and use of biomarkers and surrogate outcomes understood. Prominent issues in trial implementation include developing a manual of operations, trial registration, subject recruitment and retention, use of a data coordinating center, and data and safety monitoring. Interpretation of clinical trials requires understanding differences between efficacy and effectiveness; superiority, equivalence, and non-inferiority; intent-to-treat; primary and secondary analyses; and limitations of unregistered small clinical trials compared with large multi-center Phase III trials that are more likely to be representative of a population and change clinical practice or public health policy.

A randomized clinical multicentre trial comparing enamel matrix derivative and membrane treatment of buccal class II furcation involvement in mandibular molars. Part III: patient factors and treatment outcome

OBJECTIVE

Evaluation of effects of patient factors on the outcome of regenerative treatment of buccal mandibular class II furcation defects.

MATERIAL AND METHODS

Fifty-one patients were recruited. In the intention-to-treat population 21 patients were allocated into the sequence left treatment with enamel matrix protein derivative (EMD) and right guided tissue regeneration (GTR) and 27 in the sequence left GTR and right EMD. Evaluated patient factors were: smoking, age, gender, hypertension and oral hygiene status. Outcome parameters included change of: (a) horizontal depth of the defect at the deepest point (b) distance from the fornix of the furcation to bone crest of the defect, (c) distance from stent to the bottom of the defect, (d) pocket depth and (e) attachment level at the middle of the furcation.

RESULTS

In patients 54 years of age and older, in males, in non-smokers and in patients with "poor" hygiene EMD-treated sites showed a significant higher mean reduction of the parameters d (age), b (gender, hygiene) a (smoking, hygiene) when compared with sites treated with GTR.

CONCLUSIONS

These data provided an indication of a possible effect of patient factors on the outcome of regenerative treatment of buccal mandibular class II furcation defects.

Recruitment and Accrual of Women in a Placebo-Controlled Clinical Pilot Study on Manual Therapy

OBJECTIVE

To investigate the accrual rates and recruitment processes among 3 Midwestern sites during a pilot study on manual therapy for chronic pelvic pain.

DESIGN

Multisite pilot study for a randomized, placebo-controlled clinical trial.

SETTING

Three chiropractic institutions in or near major metropolitan cities in the Midwestern United States.

SUBJECTS

Thirty-nine women aged 18 to 45 with chronic pelvic pain of at least 6 months duration, diagnosed by a board certified gynecologist.

MAIN OUTCOME MEASURES

The method of recruitment was collected for each individual who responded to an advertisement and completed an interviewer-administered telephone screen. Participants who were willing and eligible after 3 baseline visits were entered into a randomized clinical trial. The number of responses and accrual rates were determined for the overall study, each of the 3 treatment sites, and each of the 5 recruitment efforts.

RESULTS

In this study, 355 women were screened over the telephone and 39 were randomized, making the rate of randomization approximately 10%. The most effective recruitment methods leading to randomization were direct mail (38%) and radio advertisements (34%). However, success of the recruitment process differed by site.

CONCLUSIONS

Based on the accrual of this multisite pilot study, a full-scale trial would not be feasible using this study's parameters. However, useful information was gained on recruitment effectiveness, eligibility criteria, and screening protocols among the 3 metropolitan sites.

Response to direct and indirect recruitment for a randomised dental clinical trial in a multicultural population of elders

OBJECTIVES

Recruitment for randomised clinical trials and community-based studies has received little attention in the dental literature. The goal of this study was to report on our experiences with direct and indirect recruitment methods for a trial to prevent tooth loss in elders.

METHODS

A direct approach, consisting of an introductory lecture with the help of a local contact person in each of the nine community centres, resulted in 208 recruits mostly from minority non-English speaking communities (52%), whereas the other 192 recruits who responded to newspaper announcements (48%) were, in large part, from the English-speaking community.

RESULTS

The response suggests that a more direct and culturally specific approach is more productive when recruiting elders from ethnic minority groups, whereas elders from the dominant culture can be recruited indirectly and for about half the financial cost through newspaper announcements.

CONCLUSION

We conclude, therefore, that both direct and indirect methods are needed to recruit a multiethnic sample of subjects for a trial.

Attrition and retention of ethnically diverse subjects in a multicenter randomized controlled research trial

Recruitment and retention of subjects is critically important for the conduct of randomized clinical trials. When significant effort is given toward recruiting members of ethnic minorities in a sample, a similar rate of retention for all subgroups of subjects is essential. Little is known about why research subjects withdraw consent to participate in research and whether attrition is influenced by ethnicity or other factors. The purpose of this study was to determine the reasons for withdrawal from a large, multicenter randomized trial and whether these reasons differed among ethnic and gender subgroups. Additionally, we were interested in comparing withdrawn subjects to matched subjects who stayed in the trial to determine what factors encouraged full study completion. Using a cohort survey design, adult subjects (n = 35) who withdrew from a large, multicenter randomized trial and matched subjects who completed the study (n = 35) were interviewed by telephone after study completion. Subjects who withdrew consent tended to be female and members of ethnic minorities. The most frequent problems-reported significantly more often by subjects who withdrew consent compared to matched retained subjects-were interference with work, lack of time, complicated and cumbersome record-keeping requirements, difficult study medicine regimens, and difficulty rescheduling appointments due to lack of flexibility on the part of study personnel. Only 17% of withdrawn subjects were satisfied with the overall research experience compared to 52% of matched retained subjects. Matched subjects who completed all required visits in the randomized controlled trial reported three reasons that promoted completion: remuneration, commitment to finish, and belief that the study was important.

Challenges in palliative care research; recruitment, attrition and compliance: experience from a randomized controlled trial

Randomized controlled trials (RCTs) in palliative cancer care often experience methodological problems. In this paper we discuss issues of major concern, including recruitment, patient attrition and compliance, arising from an RCT that compared comprehensive palliative care to conventional care. The main criteria for trial entry were incurable malignant disease and a survival expectancy of between 2 and 9 months. Patients' health-related quality of life (HRQL), self-assessed by multi-item questionnaires, was a defined endpoint. The planned number of patients was successfully recruited, although the patients were referred late in the course of their disease so that follow-up tended to be short. Compliance in completing HRQL questionnaires was good up to 1 month before the patient's death; but in the final weeks it was found to drop substantially. Based on our experience, recommendations are given for those planning similar research. Procedures for improving patient recruitment are suggested, stressing the need for local data management, repeated information to referral sources, extensive screening for potentially eligible patients and simple referral routines. Precise inclusion criteria, including prognostic factors other than physicians' estimates of life expectancy, should be used to ensure a sufficient follow-up period. For HRQL assessment, multi-item questionnaires can achieve excellent compliance up to 1 month before patients' death, but in order to evaluate the very final weeks of life we recommend the use of simpler methods.

Generalizability of the added benefits of guided tissue regeneration in the treatment of deep intrabony defects. Evaluation in a multi-center randomized controlled clinical trial

BACKGROUND

Several studies have shown that GTR therapy of intrabony defects results in significantly better outcomes than access flap alone. Most of the available data, however, have been produced in highly controlled research environments by a small group of investigators. Generalizability of results to different clinicians and different subject populations has not been evaluated so far.

METHODS

This parallel group study involved 143 patients recruited in a practice-based research network of 11 offices in 7 countries. It was designed to evaluate: 1) the applicability of the documented added benefits of GTR in the treatment of intrabony defects to different populations, and 2) the generalizability of the expected results to different clinicians. GTR was compared to access flap alone. Defects, one in each patient, were accessed with a previously described papilla preservation flap in both the test and control group. In addition, GTR sites received application of a bioabsorbable poly-D,L-lactide-co-glycolide membrane. A stringent plaque control regimen was enforced in all patients during the 1-year observation period. Outcomes included gains in clinical attachment (CAL) and reductions in probing depth.

RESULTS

Observed gains in CAL were 2.18 +/- 1.46 mm for access flap and 3.04 +/- 1.64 mm for the GTR-treated group. The treatment-associated difference was statistically significant (P = 0.03) after correcting for both center effect and defect anatomy. Among the various centers, a 1.73 mm difference in CAL gain was observed. This is a clinically relevant amount, which underlines the significance of center variability in the outcome of periodontal surgical procedures. A frequency distribution analysis of the obtained CAL gains indicated that GTR treatment of deep intrabony defects decreased, with respect to the access flap control, the probability of obtaining only a modest attachment gain at 1 year. Conversely, CAL gains of 4 mm or more were observed in more than 40% of GTR-treated defects and in less than 20% of the controls (P < 0.0001).

CONCLUSIONS

These data indicate that GTR therapy of deep intrabony defects performed by different clinicians on various patient populations resulted in both greater amounts and improved predictability of CAL gains than access flap alone.