Reviewer's report
Title:Multiplicative Disadvantage of Being an Unmarried and Inadequately
Insured Woman Living in Poverty with Colon Cancer: Historical Cohort in
California
Version:2Date:3 November 2014
Reviewer: Melissa Clark
Reviewer's report:
This is an interesting manuscript about the disadvantages of being an unmarried
and inadequately insured woman living in poverty on receipt of chemotherapy
and survival from colon cancer.
Major Compulsory Revisions
1. Overall, more information would be helpful about the choice of chemotherapy
for colon cancer as the exemplar for exploring this multiplicative effect of
insurance, poverty, and marital status? Why colon cancer? Why chemotherapy
specifically? For example, why not treatment for heart disease? What about
chemotherapy for colon cancer makes this outcome particularly relevant for
addressing the multiplicative disadvantage hypothesis? The authors use the term
secondary analysis on line 131, which implies that they intend for there to be a
primary analysis, which I assume to be the chemotherapy outcome. It would be
helpful if more information was added about the outcomes chosen and why the
analyses were divided into primary and secondary ones with regard to the
research question.
2. Lines 115-116: Given that all analyses include the health insurance variable,
there is concern about the way that the construction of the health insurance
variable was explained and interpreted. Given that the majority of colon cancer
patients will be over age 65, most will be eligible for Medicare. Therefore, what
does adequate insurance imply with regard to private insurance. Does this mean
that they had private supplemental insurance? Does Medicare in the inadequate
category refer to Medicare only without any private supplemental coverage? The
way that the health insurance variable was created and/or how it has been
presented is very important given the manuscript's conclusions.
3. Lines 172-173: It is not clear what data from this study provide direct evidence
that the receipt of chemotherapy is related to survival chances among those with
non-localized and non-metastasized disease particularly because there were no
differences in survival. More detail here would be helpful. Similarly, more detail
would be helpful about the authors' conclusions that chemotherapy is associated
with quality of life among those with metastasized disease.
Minor Essential Revisions
4. Line 104: What do the authors mean by the fact that they "serendipitously"
explore the 4-way hypothesis?
5. Is the information presented about the power analysis for the survival analyses
specifically or for all analyses?
6. Discussion: While the authors present compelling arguments about the
economic disadvantages for unmarried women with regard to chemotherapy
receipt, there are other potential explanations that warrant mention including the
fact that they may have smaller social networks to drive them to chemotherapy
and/or care for them when they are ill from the chemotherapy. Further, there is a
body of literature about the social support among married versus unmarried
individuals, including the provision of emotional and instrumental support with
regard to a health condition. Addition of some of this literature would strengthen
the discussion.
Discretionary Revisions
7. Lines 91-93: What are gold, platinum, bronze and silver health plans?
8. Lines 111-112: The categories used for socioeconomic status are not clear. It
appears that words may be missing from this sentence.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.