Due to the wide availability of different treatment options for hypercalcemia of malignancy, the aim of this systematic review is to identify important contextual and decisional factors that affect choices for therapies of hypercalcemia of malignancy in adult patients.
Information sources and search strategy
We conducted a comprehensive search using the following online databases: Medline (OVID), Pubmed, Embase.com, the Cochrane Library and CINAHL (EBSCO). The research team developed a search strategy for each data base using MESH terms and keywords related to malignancy, hypercalcemia and factors guiding therapy decision such as patients’ values and preferences, acceptability, equity, cost-effectiveness and feasibility, that was applied to adults, and limited to the last 10 years. We did not include any language restrictions. The strategy was reviewed and verified by the medical librarian at the American university of Beirut (LH), and two methodologists, at the Mayo Evidence Based Center (MHM) and the McMaster University (TP) (Appendix 2A). We also developed and executed another independent search using Medline, without any time limit, and the results were combined with the original search (Appendix 2B). We also plan to identify papers by hand searching references from the included studies.
Eligibility criteria
We included observational studies, trials, reviews and qualitative studies conducted in adult patients (≥ 18 years of age) with hypercalcemia of malignancy. We included studies reporting on pharmacological therapy such as bisphosphonates, denosumab, diuretics, calcitonin, and calcimimetics as well as conservative management including hydration, avoiding calcium rich diet and vitamin D supplementation. We excluded case reports, studies conducted in the pediatric population or in patients with hypercalcemia from a condition unrelated to malignancy for example parathyroid disease, Familial Hypocalciuric Hypercalcemia (FHH), vitamin D intoxication, and side effects of medications.
Outcomes
Our outcomes of interest are EtD factors:
- Patients or physicians values (how patients or physicians value each outcome in terms of its importance to their context and daily life)
- Cost and resources (cost effectiveness, actual charges, out of pocket costs)
- Acceptability (of treatment options and their method of administration)
- Feasibility (of the intervention as it relates to the health care environment)
- Equity (whether the intervention would exacerbate health disparities or create inequities)
We will exclude studies with inadequate outcome measurement or reporting.
Study Selection
We downloaded the literature search results into Covidence software (Covidence 2020) (24). We developed and pilot tested a screening sheet for title and abstract and another for the full texts (Appendix 3), based on our exclusion and inclusion criteria of individual studies. We performed a calibration exercise to familiarize the reviewers with the screening process.
All reviewers (AB, MR, TP, MHM, GEHF) contributed to pilot testing the screening at the title and abstract level for 100 citations. Two reviewers (AB, MR) then independently screened the remaining titles and abstracts using the screening sheet developed (Appendix 3A). We retrieved the full texts of all included citations. Two reviewers (AB, MR) screened these records independently and in duplicate using the full text screening guide (Appendix 3B). All disagreements throughout the screening process were resolved through discussion or with the help of a third reviewer as needed (TP, MHM, GEHF). All reasons for exclusion were recorded.
Data collection and abstraction
Following the full text screening, two reviewers (AB, MR) will complete data abstraction independently and in duplicate using standardized data collection tables (Appendix 4). We will implement a calibration exercise to familiarize the reviewers with the process. If any disagreement occurs during data abstraction, it will be resolved through discussion or with the help of a third reviewer as needed (TP, MHM, GEHF). We will contact the authors in case of remaining disagreements and uncertainties. We will extract the first author’s name, date of publication and the study design, and will collect data on the characteristics, methodology and results of each of the included studies (Appendix 4). In case of any missing data, we will contact the authors of the individual studies to obtain the relevant information.
Data Synthesis
The methodological quality of the included studies will be evaluated using tools appropriate for each study design, including randomized trials, cohort and case control studies, case series, and qualitative research (25-30).
Data will be analyzed thematically and presented narratively. Two independent reviewers will identify themes from each article until saturation and reach consensus on how the themes would converge into unique. A third reviewer will adjudicate when consensus is not reached.
The certainty of evidence derived from the studies will be evaluated using the GRADE-CERQual approach which appraises qualitative research domains analogous to GRADE. This approach focuses on the methodological limitations of the studies, coherence, adequacy, and relevance of the findings (30).