Preparedness is defined as a caregiver’s readiness for the caregiving roles, such as fulfilling the physical and emotional requirements of the patient, planning care, and managing the stressors.1,2Preparedness consists of 2 domains: emotional and practical preparedness.3,4 Emotional preparedness covers coping with a broad range of emotions from burden in the caregiving process to the loss of the patient. Practical preparedness includes adapting to necessary changes in daily life, such as assuming the new household, financial, and other daily responsibilities. Both emotional and practical preparedness for the caregiving process may balance the negative impacts of caregiving.5 Studies have reported that the caregivers who felt prepared experienced fewer worries during caregiving.6,7 In addition, increasing the caregivers’ preparedness to care is associated with a lower burden.8,9 Scherbring10 reported that every 1-unit increase in the preparedness to care resulted in a decrease of approximately 17% in the caregiver’s burden. Considering its effect on caregiver burden, the preparedness to care is of critical importance for family members who care for patients in need of long-term support.2

Cancer patients need long-term care because of numerous symptoms, including pain, fatigue, sleep issues, depression, anxiety, and stress.11–13 The symptom burden results in the cancer patients encountering difficulties in their daily activities, such as eating, walking, and even communicating. Therefore, the dependence of cancer patients on family caregivers increases.14,15 Family caregivers have to put several efforts into supporting the daily requirements of patients, decrease their symptom burden, and endure the stress of having a loved one experiencing a life-threatening disease.7,16 The family caregivers have essential responsibilities, including symptom management, medication monitoring, transportation, care coordination, and emotional support.17,18 The family caregivers endeavoring to fulfill both familial and caregiver roles may face several problems associated with their own physical and psychological health, daily-life activities, work life, social activities, and recreation.19,20 The family caregivers may feel highly burdened during the illness period as they deal with several challenges associated with loss and death during the palliative care period.9,21 Usually, the caregivers experiencing these physical and psychosocial problems initially define caregiving as a daunting task.22 According to recent studies, the caregivers reported feeling heavily burdened and having poor preparedness to care.1,2 The lack of caregiver preparedness to provide complex care may increase their physical problems, such as lack of sleep and fatigue. These physical problems decrease their well-being and overall quality of life.6,8 In addition, when the physical and psychological well-being of the caregivers is reduced, the status of the patients also worsens.3 In particular, the patients with caregivers unprepared for care can experience higher symptom burden, anxiety, and stress due to inadequate symptom management and emotional support.3,22

To foster beneficial effects of the preparedness to care on caregivers and patients, several interventions are required for better management of the care process and to increase the level of caregiving preparedness.10 These interventions that are aimed at increasing the readiness among the caregivers are important during the illness period for both patients and caregivers.1,23 Interventions include educational, supportive, self-care, and psychoeducational programs conducted by a nurse-led or an interdisciplinary team.5,7,24 Although the educational, supportive, and self-care programs are named differently in studies, they are very similar in content.23,25,26 These interventions address the roles of caregivers, information about the disease and treatments, symptom management, prevention of infection, nutrition, and coping with stress.26,27

Psychoeducation is an evidence-based therapeutic intervention for caregivers that provides information and support to better understand and cope with illness.28 Psychoeducation for caregivers aims to promote psychological well-being, resolve existential issues, prepare for the ill relative’s death, and the grief process.5 Overall, the content of these educational, supportive, self-care, and psychoeducational interventions is intended to increase the preparedness of caregivers in alignment with certain theoretical frameworks. Studies usually use the theoretical framework of Andershed and Ternestedt29 for caregiving interventions for family members.5 This framework defines family caregivers’ roles in palliative caregiving and focuses on knowing, being, and doing. Knowing is essential for family caregivers and is linked with an awareness of the patient’s critical status and the roles of caregivers. Being is associated with the management of the caregiver’s own emotion as well as the patient’s. Doing consists of the practical aspects of caregiving. The overall aim of this theoretical framework is to promote preparedness for caregiving among family caregivers through interventions.29

To the best of our knowledge, the literature contains a few intervention studies evaluating the preparedness to care among caregivers.5,24,26 A systematic review investigating the effects of nursing interventions on family caregivers of end-of-life patients emphasized that interventions applied to caregivers have a significant effect on increasing preparedness to care.30 However, the effect of the interventions applied to caregivers and their preparedness to care is not clear due to some differences in the intervention content, duration, and sample characteristics. Future studies involving interventions for caregivers need to take into account content and duration of the intervention. It is essential to present interventions aimed at increasing the preparedness of caregivers from a holistic perspective.

This meta-analysis attempts to provide an overview of the effects of interventions on the preparedness of caregivers of cancer patients. The objectives of this meta-analysis were as follows: (1) to summarize the interventions applied to the caregivers of cancer patients on their preparedness to care, (2) to reveal the effects of these different interventions on the preparedness to care, and (3) to determine the methodological quality and evidence level of the included studies. The results of this meta-analysis provide evidence-based recommendations for the interventions on the preparedness to care aimed for caregivers of cancer patients.

Methods Study Design

A meta-analysis study design was adopted. This study was reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines. The Participants, Intervention, Comparison, and Outcome (PICO) strategy was applied to formulate the research questions.31 The family caregivers of the cancer patients formed the participants (P) of the present meta-analysis. The interventions (I) included all the educational, supportive, self-care, and psychoeducational interventions, and all the studies applying or not applying the comparison (C) strategy. Preparedness to care was accepted as the outcome (O) variable. According to this PICO strategy, the formulated research questions were as follows: “Are the interventions applied to the family caregivers effective on the preparedness to care?” and “If effective, what is the level of effectiveness of these interventions on the caregivers’ preparedness to care?”

Search Strategy

ScienceDirect, Scopus, Cochrane Central Register of Controlled Trials, Web of Science, MEDLINE, and PubMed were searched for relevant studies published between 2000 and 2020 years. The search strategy involved using the following MeSH terms and keywords for all the databases: (1) “Caregivers” OR “Carers” OR “Family caregivers” OR “Spouse caregivers,” AND (2) “Oncology” OR “Cancer” OR “Neoplasm” OR “Neoplasia” OR “Tumors” OR “Malignancy,” AND (3) “Preparedness.” The initial literature review for the present meta-analysis was performed between July 2020 and August 2020, and the search strategy was repeated during September 2020 to October 2020 to update the meta-analysis before publication (Supplemental Digital Content 1, https://links.lww.com/CN/A39).

Inclusion and Exclusion Criteria

The inclusion criteria were as follows: (1) studies involving caregivers of cancer patients of any diagnosis and at any stage of cancer; (2) studies conducted with adults older than 18 years; (3) studies that reported the caregivers’ preparedness to care with no limitations in the assessment scales; (4) studies that included intervention for the preparedness to care such as educational, supportive, self-care, and psychoeducation; (5) studies published in English and between the years 2000 and 2020; and (6) studies with an experimental design (including randomized controlled trials [RCTs], non-RCTs, and 1-group pretest-posttest design studies). The exclusion criteria were as follows: (1) studies designed as a review, case study, cross-sectional study, or qualitative study; (2) gray literature including studies published in non–peer-reviewed journals and those not controlled by commercial publishing organizations; (3) thesis, expert opinions, letters, and conference papers; and (4) unpublished studies. As the present review focused on the studies designed specifically for assessing the preparedness to care among the family caregivers of cancer patients, the scales that assessed quality of life, symptoms, or psychosocial status were not included.

Data Extraction

The Endnote X8 reference-management software package was used to aggregate citations from all databases in this review. After discarding the duplicate studies, the titles and abstracts of all the studies were screened according to the inclusion criteria by 2 investigators. Subsequently, all the full-text articles were reviewed independently by the 2 authors according to the inclusion and exclusion criteria. The data from the included studies were collected into a previously prepared data collection form, which included the following titles: first author, publication date, country, study design, type of patients, inclusion criteria, sample size, age of caregivers, gender of caregivers, intervention type, duration of intervention, intervention strategies, control strategies, training providers, scales, assessment times, and results. Any discrepancies in the extracted data were resolved through discussion.

Quality Appraisal

The levels of evidence were classified according to the evidence level hierarchy adopted by the Joanna Briggs Institute,32,33 which includes 7 levels from 1 to 7. Evidence level 1 includes a systematic review or meta-analysis of all the relevant RCTs. Evidence level 2 presents the results from a well-designed RCT. Evidence level 3 comprises the findings of well-designed non-RCTs. Evidence level 4 considers case-control or cohort studies. Evidence level 5 includes a meta-analysis of descriptive and qualitative studies. Evidence level 6 contains the results of qualitative or descriptive studies. Finally, evidence level 7 includes reports and/or opinions of the experts. The present meta-analysis included studies at evidence levels 2, 3, and 4. The methodological quality was assessed using the Quality Assessment Tool for Quantitative Studies of the Effective Public Health Practice Project and is used to assess intervention studies, including RCTs, non-RCTs, and pretest-posttest studies. This tool contains 6 items, including the design, selection bias, blinding, confounders, method of data collection, and withdrawal from the study. Each item on the tool is scored as “strong,” “moderate,” or “weak.” The global rating for each study is obtained. The studies with no weak scores indicate a strong methodological quality, the studies with 1 weak score indicate a moderate methodological quality, and the studies with 2 or more weak scores indicate poor methodological quality.34,35 The quality of the included studies was evaluated independently by the 2 authors, and a consensus was achieved through discussion.

Outcome

The effects of interventions on the preparedness to care of the caregivers of cancer patients were analyzed. All the included studies used the Preparedness for Caregiving Scale designed originally by Archbold et al.4 This scale assesses the caregiver’s perception of their preparedness to manage the roles and stresses of caregiving. The scale contains 8 items, each of which is scored from 0 to 4. The total score, obtained by summing the individual scores for all the items, ranges from 0 to 32. A high score indicates greater feelings of preparedness to care. This scale has acceptable reliability when administered to the caregivers of cancer patients, as evidenced by the Cronbach’s α coefficient of 0.72 reported previously.4 Henriksson et al36 reported a Cronbach’s α coefficient of 0.90 for this scale in a sample of caregivers of patients receiving palliative care.

Data Synthesis

The outcomes were analyzed using the Comprehensive Meta-Analysis software version 3.0 (Biostat, Englewood, New Jersey). The Q statistic and I2 statistics were used to evaluate heterogeneity. The I2 statistics values were categorized into no (0%-25%), low (25%-50%), moderate (50%-75%), and high (75%-100%) heterogeneity. A fixed-effects model was used to present the studies in the case of I2 ≤ 50% and P > .1; otherwise, a random-effects model was applied. In addition, the τ2 statistic was used to complement the assessment of heterogeneity and reveal the variance among the studies. The standardized mean difference (SMD) with a 95% confidence interval (CI) was used to report the effect size. Cohen’s d was adopted as the measure of the effect size for each study and was weighted by the sample size of that study. These d values were then averaged to calculate the overall effect size. The d value was converted to a z value. Moreover, forest plots were prepared to visualize the effect size and the SMD with 95% CI. Publication bias was examined visually using funnel plots. An asymmetrical funnel plot represents a potential publication bias. The Egger regression test was applied to test the asymmetrical funnel plot. Subgroup analysis and meta-regression were performed to assess any potential moderating variables. The subgroup analysis and meta-regression were performed according to the sample size, age, gender, duration of the intervention, the training providers, intervention setting, and the type of intervention.

Results Study Selection

A total of 1975 studies were obtained upon searching the databases, of which 1454 were duplicates. The titles and abstracts of the remaining studies were screened according to the inclusion and exclusion criteria, and 503 studies were excluded for not fulfilling the inclusion criteria. The full texts of the remaining 18 studies were reviewed according to the inclusion criteria, and 7 studies were excluded because these did not evaluate the caregivers’ preparedness to care. The remaining 11 studies were finally included in the present meta-analysis (Figure 1).

Figure 1:

Study flow diagram.

Study Characteristics

Most of the selected studies were from Australia (n = 5), whereas the remaining ones were conducted in the United States (n = 4), Sweden (n = 1), and the United Kingdom (n = 1). Four of the studies were designed as an RCT, whereas the remaining ones were designed as a 1-group pretest-posttest (n = 5) or non-RCT (n = 2). Approximately half of the studies (n = 6) included caregivers of cancer patients. Eight studies did not focus on a specific cancer type and included caregivers of patients with different cancer types, such as lung, breast, and colon cancer. Three studies focused on a specific cancer type, including 2 studies with caregivers of non–small-cell lung cancer patients26,37 and on1 study with caregivers of high-grade glioma patients.24 The sample size of the studies ranged from 31 enrolled23,24 to 354 enrolled,26 which further decreased (ranging between 22 and 344) because of attrition during the intervention (Table 1).

Table 1 - Characteristics of Reviewed Studies Study (Year) Country Study Design Type of Patients Inclusion Criteria Sample Age, Mean (SD), y Gender 1. Hudson et al28 (2005) Australia A randomized controlled trial Palliative care patients - Aged at least 18 y
- Not having an intellectual or psychiatric illness that would preclude completion of study
- Caregivers who speak English Intervention, 54/20
Control, 52/25 60.7 (13.9) Female, 65.1%
Male, 34.9% 2. Hudson et al38 (2009) Australia A 1-group pretest-posttest design Palliative care patients with advanced cancer - Aged at least 18 y
- Not having a pronounced psychological distress
- Caregivers who speak and understand English 156/96 59 Female, 70%
Male, 30% 3. Hudson et al39 (2012) Australia A 1-group pretest-posttest design Palliative care patients - Aged at least 18 y
- Caregivers who speak and read English 245/126 57.1 (14.7) Female, 66.7%
Male, 33.3% 4. Potter et al25 (2012) United States A 1-group pretest-posttest design All types of cancer - Aged at least 18 y
- Caregivers who speak and understand English
- Having a DVD player in the home 38/22 57.3 (14.7) Female, 55.3%
Male, 44.7% 5. Hudson et al40 (2013) Australia A randomized controlled trial Advanced cancer patients receiving home-based palliative care - Aged at least 18 y
- Caregivers who speak and understand English
- Not having emotional distress precluding them from completing questionnaires Intervention, 150/80
Control, 148/81 59.0 (13.9) Female, 70%
Male, 30% 6. Luker et al23 (2015) United Kingdom A 1-group pretest-posttest design End-of-life patients receiving palliative care - Aged at least 18 y
- Resided with the patient 31/24 62 Female, 74%
Male, 26% 7. Sun et al26 (2015) United States A nonrandomized controlled trial Patients with non–small-cell lung cancer - Aged at least 21 y Intervention, 197/191
Control, 157/153 57.3 (13.7) Female, 64.1%
Male, 37.9% 8. Hendrix et al7 (2016) United States A randomized controlled trial All types of cancer under hospice care - Aged at least 18 y
- Expected to care for patients after discharge
- Willing to spend at least 2 h in the hospital for the training
- Caregivers who speak and read English Intervention, 66/38
Control, 64/38 55.3 (13.2) Female, 83.3%
Male, 16.7% 9. Holm et al5 (2016) Sweden A randomized control trial Palliative care patients - Aged at least 18 y
- Caregivers who speak and read Swedish Intervention, 98/89
Control, 96/88 61.5 (13.8) Female, 66.4%
Male, 33.6% 10. Nguyen et al37 (2018) United States A nonrandomized controlled trial Patients with non–small-cell lung cancer - Aged at least 18 y
- Closely involved in their care of the patient Intervention, 60/39
Control, 62/40 63.4 (11.9) Female, 59.8%
Male, 40.2% 11. Philip et al24 (2019) Australia A 1-group pretest-posttest design Patients with high-grade glioma - Aged at least 18 y
- Willing to participate in the study 31/29 55.7 (12.9) Female, 58.1%
Male, 41.9%
Intervention

Eight of the studies invited the caregivers to the clinic for the training process, whereas 3 studies involved home visits for the education of caregivers.23,28,40 Telephone interviews were conducted in 3 studies to identify the requirements of the caregivers or to decide a suitable date for the home visit.24,28,40 The training sessions were conducted in groups in 3 of the studies,5,38,39 whereas interventions in the remaining 8 studies were based on individual sessions. The duration of the interventions in the studies varied from 3 days39 to 12 weeks.24,37 Most of the studies (n = 5) included a psychoeducation program, whereas the other studies conducted an educational program (n = 3), a supportive program (n = 2), or self-care support for the caregivers (n = 1). The content of the interventions included symptom management, prevention of infection, maintenance of nutrition, and several emotional support topics for the patients, besides focusing on the important roles of caregivers in managing the care process, self-care of the caregivers, preparedness for their relative’s death, and support services to assist the caregivers. Certain interventions also emphasized stress management among the caregivers and, therefore, trained the caregivers in deep breathing, progressive muscle relaxation, and pleasant imagery.7,28 In the 6 studies that included a control group, the control groups were provided with standard care, including information regarding emergency visits, palliative care services, and standardized training (Table 2).

Table 2 - Intervention Strategies and Results of Reviewed Studies, Continued Study (Year) Intervention Duration of Intervention Intervention Strategies Control Strategies Training Providers Scales Assessment Times Results 1. Hudson et al28 (2005) A psychoeducation program 4 wk - The intervention consisted of 2 home visits and a phone call between the 2 visits.
- The caregivers were given a caregiver guidebook and audiotape by the nurse.
- The caregiver guidebook provided written information related to important aspects of caring for a dying person.
- The audiotape included self-care strategies and a structured relaxation exercise for stress management. The control group received standard care including access to 24-h phone from nurses and information about emergency visits. The palliative care nurse PCS - Baseline
- 5 wk
- 8 wk after patient death No intervention effects were determined in terms of preparedness to care. 2. Hudson et al38 (2009) A group psychoeducation program 3 wk - The main content of the Caregivers Group Education Program (CGEP) was based on a psychoeducation intervention.
- The CGEP performed in 3 sessions (1.5 h each) over a 3-wk period.
- The sessions focused on the important role of caregivers, strategies for self-care (caregiver’s well-being) and symptom management, and strategies for caring for a person when death is approaching and an overview of bereavement supports for the family caregivers.
- Carers received the caregiver guidebook designed specifically for preparing family caregivers. — An interdisciplinary team including social workers and nurses working in home-based palliative care services PCS - Baseline
- 3 wk
- 5 wk The intervention had a statistically significant positive effect on preparedness. 3. Hudson et al39 (2012) A group psychoeducation program 3 d - The intervention involved 5 special topics: what is palliative care, the typical role of family caregivers, support services available to assist caregivers, preparing for the future, and self-care strategies for caregivers.
- At the end of the program, family caregivers were invited to meet individually with relevant members of the multidisciplinary team to discuss their needs.
- Each education session was of 1.5-h duration. — An interdisciplinary team PCS - Baseline
- 3 d There were statistically significant improvements in caregivers’ sense of preparedness (P < .001; effect size, 0.43). 4. Potter et al25 (2012) An educational program for fall prevention skills 4 wk - The DVD program design and content were developed using Schumacher and colleagues’ “Transactional Model of Cancer Family Caregiving Skill.”
- The content addressed the information dealing with the symptoms of illness and treatments that place cancer patients at risk for falling.
- The program prepared caregivers to make decisions and performs processes of care pertinent to fall prevention.
- The family caregivers had 4 wk to view the DVD in their home. — Nurses PCS - Baseline
- 4 wk
- 12 wk Family caregivers did not significantly increase their perceptions of preparedness after viewing the DVD. However, there was an overall increase in the average preparedness score from a mean score of 2.91 to one of 3.12. 5. Hudson et al40 (2013) A psychoeducation program 4 wk - The intervention was delivered over 4 wk.
- Nurses assessed the needs of caregivers by phone and consisted of the care plan.
- Caregivers were given the family caregiver guidebook to promote psychological well-being.
- The family caregivers were prepared for their relative’s death and the grief process with a home visit. Standard care Family caregiver support nurses who assisted the local palliative care service to assess caregiver needs, establish a care plan, and provide additional caregiver support. PCS - Baseline
- 5 wk
- 8 wk The intervention provided significant improvements in participants’ levels of preparedness. 6. Luker et al23 (2015) A supportive program 4 wk - The researcher had introduced and explained the booklet to the caregivers at the first home visit.
- Caregivers used the booklet for at least a month.
- The booklet contained practical information that was accessible and readable by caregivers.
- The booklet included the following topics: pain, common bladder problems, common bowel problems, loss of appetite, nausea and vomiting, breathlessness, pressure sores, mobility, equipment, personal care, emotional aspects, support for caregivers, nearing death, and bereavement. — An interdisciplinary team including nurses and general practitioners PCS - Baseline
- 4/6 wk There were no statistically significant improvements in the preparedness of caregivers. 7. Sun et al26 (2015) A self-care support for caregivers 7 wk - The study’s conceptual framework included adult teaching principles of the National Comprehensive Cancer Network Guidelines for Distress Screening.
- The caregivers also received 4 educational sessions with content categorized by the 4 quality of life domains including physical, psychological, social, and spiritual well-being.
- The teaching sessions averaged 28 min, and a guideline was given to caregivers.
- Content for caregivers also included a personalized self-care plan. The caregivers and patients received standard care including all supportive and palliative care services while on the study. An interdisciplinary team including nurses, palliative medicine clinicians, thoracic surgeons, medical oncologists, a geriatric oncologist, a pulmonologist, a social worker, a chaplain, a dietitian, and a physical therapist PCS - Baseline
- 7 wk
- 12 wk No significant difference was observed between groups for caregiver skills preparedness. 8. Hendrix et al7 (2016) An educational program 4 wk - The nurse provided training in symptom management strategies including prevention of infection, management of fatigue, pain control, and maintenance of nutrition.
- The nurse also provided technical care skills if warranted (eg, care of a central catheter).
- The skills training for stress management for caregivers focused on deep breathing, progressive muscle relaxation, and pleasant imagery.
- Training lasted 1-2 h, and if desired, caregivers could spread this out over 2 sessions. Caregivers received standardized training about local community resources, home health, hospice, and palliative care. The nurse interventionist trained to deliver both arms of the intervention PCS - Baseline
- 2 wk
- 4 wk The intervention group had a greater increase in preparation for caregiving at the posttraining assessment compared with the control group. 9. Holm et al5 (2016) A group psychoeducation program 3 wk - The guideline was developed based on the theoretical framework of Andershed and Ternestedt relating to the principal knowledge seeking and support needs of family caregivers.
- The intervention program was delivered in a group format including 3 sessions, covering 2 h once a week over 3 wk.
- The intervention included the following: palliative diagnoses and symptom relief, daily care and nutrition problems, and support and existential issues. The control group received standard support. An interdisciplinary team including a physician, a nurse, and a social worker/priest PCS - Baseline
- 3 wk
- 8 wk The intervention group had significantly increased their preparedness for caregiving compared with the control group. 10. Nguyen et al37 (2018) An educational program 12 wk - The interdisciplinary care plans were created for patients and caregivers.
- The patients and caregivers were followed for any additional support services by the nurses.
- The first patient session covered physical and psychological issues, and the second session included social and spiritual issues.
- A third teaching session was held with the caregivers alone. Standard care The clinic palliative care registered nurses PCS - Baseline
- 4 wk
- 12 wk Caregivers in the intervention group had improvements in preparedness compared with the control group. 11. Philip et al24 (2019) A supportive care 12 wk - Patients were provided with a material that included generic information about high-grade gliomas, treatment options available, places to access further resources, and information including recommended websites.
- The researchers regularly screened patients and caregivers for needs via phone calls.
- Emotional support was provided for patients and caregivers.
- Coordination of care relevant to the patient’s supportive care, treatment planning, and follow-up was overseen by the cancer care coordinators; family caregivers were included in consultations and discussions where information was given. — Oncology nurses PCS - Baseline
- 2 wk
- 12 wk

Abbreviation: PCS, Preparedness for Caregiving Scale.

Quality Appraisal

Four of the studies had the evidence level of 2 (indicating a well-designed RCT), whereas 2 studies26,37 had the evidence level of 3 (representing well-designed non-RCTs). The remaining studies (n = 5) had an evidence level of 4 (representing cohort or case-control studies). The methodological quality of the included 11 studies was assessed, and the global rating of only 2 studies7,40 was evaluated as “strong,” whereas 5 studies were rated as “moderate.” The remaining 4 studies23–25,39 were rated as “weak” due to not limiting confounders, no blinding, and high dropout rates. In all included studies, a detailed explanation regarding the study was provided to the caregiver participants, which minimized selection bias. The assessment of the design of the studies revealed that 4 studies were of strong quality and 7 studies were of moderate quality. Whereas 8 of the selected studies reported that the confounding factors, such as age, gender, economic status, and duration of caregiving, which could affect the study outcomes, were limited, the remaining 3 studies did not provide any such information.23–25 Moreover, 2 of the studies involved blinding the data collectors,7,40 whereas no blinding was performed in the remaining 9 studies. In all the studies, data were collected and scored using scales that were valid and reliable. In terms of withdrawals and dropouts, 3 studies were evaluated as having a strong quality5,24,26 and 7 studies had a moderate quality. One study39 was determined to be of weak quality due to high rates of withdrawals and dropouts (Table 3).

Table 3 - The Evidence Level and Methodological Qualities of Studies Study (Year) Evidence Levela Methodological Qualityb Selection Bias Study Design Confounders Blinding Data Collection Method Withdrawals and Dropouts Global Rating 1. Hudson et al28 (2005) Level 2 Strong Strong Strong Weak Strong Moderate Moderate 2. Hudson et al38 (2009) Level 4 Strong Moderate Strong Weak Strong Moderate