Title: Determinants of the use of contraceptive methods by adolescents in the Democratic
Republic of the Congo: results of a cross-sectional survey
Version: 0 Date: 02 Aug 2022
Reviewer's report:
Mpunga and colleagues described a secondary epidemiological analysis of the variables, or “risk
factors” that were associated with decreased contraceptive use among adolescent girls (aged
15-19) in Kinshasa and Kongo Central, Democratic Republic of the Congo. The authors used
data from the Performance, Monitoring and Accountability project and performed univariate
analyses, bivariate analyses, and logistic regression. They found that among the 943 adolescent
girls included in the study, approximately 20% used contraception, with 12% using “modern”
contraceptive methods. They did not find any statistical differences by regions with respect to
modern contraceptive use, but did find that Kongo Central had less traditional contraceptive
use than Kinshasa. Interestingly, although not significant, the pattern suggests that Kongo
Central used more modern contraceptive methods than Kinshasa, which may explain this
difference. Finally, logistic regression found that knowledge of family planning methods
were significantly associated with modern contraceptive use while religion and location was
significantly associated with traditional contraceptive use.
Although this work was thoroughly conducted and is extremely relevant, as it addresses a region
that is severely underserved, I have several concerns for publication. I have outlined these
concerns below:
Major Concerns
1. Please review the manuscript for typos and grammatical errors, for example “gilrs” is
misspelled in the second sentence of the abstract.
2. Consider the level of precision of your p-value estimates. Is the study truly powered to detect
a significance value of p<0.001? Lower p-values do not mean “more” evidence. Please consider
dropping the number of significant digits in your p-values or putting all to where the study was
presumably powered (i.e. p < 0.05).
Introduction
3. Please considering toning down the “causal” language – examples are provided in the minor
concerns.
4. Please review statistics and add clarifying information – examples are provided in the minor
concerns.
Methods
5. Please clarify what size in the following sentence “using the selection probabilities
proportional to size.” Assume this is based on cluster population size?
6. For the independent variables section, please exclude the phrases “on the one hand” in the
first sentence and reformat the independent variables in prose not bullet points. Alternatively,
use a supplementary table.
7. The authors have dichotomized several continuous and categorical variables, which can result
in residual confounding. Please consider performing sensitivity analyses with untransformed
variables of interest and/or commenting in the discussion on the limitations of dichotomizing
variables that have non-binary options.
8. Further information is needed on data collection and quality control – how was the data
validated and cleaned? Or was this done previously as part of the primary PMA study (citation
needed then)? Weights were applied in the statistical analysis section?
9. For adolescent girls that used multiple contraceptive methods, how were they classified
(modern vs traditional)? What if they used a mix of modern vs traditional contraceptives?
10. The authors do not describe if they considered confounding in their models and are
interpreting all variables jointly. This should be made explicit, as several sources have identified
issues with interpreting all covariate coefficients in a regression model and using them as
quantifiers of association.
Results
11. Are figures 2-5 necessary? Would these results be better suited in a table instead of barplots?
12. This is an incorrect interpretation of the odds ratio and should not use causal language (it’s an
association): “Poor knowledge of FP increases the probability of not using modern contraceptive
methods by twenty-three times”. This incorrect interpretation and causal language is carried
throughout the logistic regression results section and needs to be altered.
13. Please see p-value comment above
Discussion
14. The authors state that there is more unmet need in Kongo Central than Kinshasa but then
state that “According to Gilda et al. [33], women with unmet FP needs cite infrequent sex,
unmarried status, and the side effects of contraceptive methods as discouraging the use of
modern contraception. These observations are consistent with the results of the present study.”
However, their study results indicate that there is more modern contraceptive use in Kongo
Central than Kinshasa. Can the authors clarify these conflicting results/expectations, particularly
in reference to the above sentences.
Minor Concerns
Abstract
1. Please first define abbreviations before their use (e.g. PMA is used in the third sentence of
the abstract but is not defined).
2. Adjust odds ratios are often abbreviated aOR not AOR – please fix throughout
3. The first sentence of the conclusion needs to be clarified (or there may be a typo)
Main Text
1. I am having trouble accessing the Guttmacher Institute 2016 Report (citation 1) but was hoping
to clarify the statement that that that “more than half [of adolescent pregnancies in developing
countries] end in abortion”? That statistic seems extremely high given issues of access to care,
legal/religious barriers, etc., particularly in rural communities. Are there additional references
to clarify this statistic?
2. Although I agree with the argument, I think the sentence needs to be toned down from “fact”
and “causal” implications that early pregnancy and dropping out leads to poverty – can you
say is associated with or some equivalent?: “In the African region, teenage pregnancies are
often followed by a drop out of schooling [7]; this fact leads to poverty, makes such teenagers
dependent on aid programs, and places a considerable burden on economies and health systems
[5,6,9].”
3. I believe “consecrating” is the wrong word in this sentence – “During the same period, unmet
needs in adults decreased from 45.8% to 38.0%, thus consecrating inequalities between adults
and adolescents [13].”
4. Can you clarify time period for this sentence: “In 12 countries, including the Democratic
Republic of the Congo (DRC), the satisfaction of demand for modern contraceptive methods
remained below 10% among the adolescent group [14].”
5. This sentence needs to be corrected “In 2016, up to six in 10 pregnancies that occurred in
Kinshasa were unplanned; most ending in unsafe abortion [24].” Based on the citation, it is
true that approximately 60% of pregnancies were unintended, but of that 61% the article states
that “43% of these pregnancies were aborted”. They later say that “two in five unintended
pregnancies end in abortion.” That is many but not most.
6. In the discussion, need to define MISC-RDC.