Investigation of Vancomycin Trough Time and Age Correlation

This report investigates the correlation between vancomycin trough time and age, employing both case-control and retrospective study designs. The research question focuses on identifying factors influencing the achievement of target vancomycin trough levels. The study design section details the methodologies, including subject selection and the rationale behind choosing these approaches to establish an association between age and vancomycin trough time. It discusses issues related to measuring exposure and outcome within each study design, highlighting the challenges and considerations. The report also addresses potential biases inherent in both retrospective and case-control studies, such as selection, measurement, and recall biases, and explains how these biases could impact the study's findings. The analytical approach section describes the statistical methods used, including the odds ratio for the case-control study and t-tests for the retrospective study, along with the sample sizes, significance levels, and assumptions made. The report concludes by emphasizing the importance of understanding the influence of age on vancomycin trough time to optimize treatment strategies.

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Trough Time of Vancomycin and Age Paper
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Trough Time of Vancomycin and Age
Research Question
What is the factor effect in reaching goal trough of vancomycin?
Design Studies and Subject Selection
In the field of Epidemiology and Biostatistics, research design studies are separated into
two groups namely observational and experimental. Under observational study design we will
choose to employ the case-control approach. Therefore, a case-control study is regarded as an
assessment under which two groups of individuals with different outcome are selected and
compared on the merit of some underlining causal attribute. The main aim in a case-control study
is to establish whether there is an association between exposure and the outcome. As such, in this
case control study will investigate goal trough time for vancomycin as a function of age. The
objective here is to establish association between age and tough time vancomycin (Mathijssen,
Houwing, & Brookhuis, 2009). With regard to experimental design studies, a retrospective study
will be employed.
Unlike a prospective design study, a retrospective study is performed after some of the
individual have developed or attained the desired outcome. The investigator/researcher is
therefore required to go back and identify a particular point in time when the participants had not
developed the desired outcome and try to establish their exposure level at that instance. It is then
the role of the investigator to determine whether a particular subject developed the desired
outcome or not. And if he/she did develop the desired outcome, it is the responsibility of the
investigator to establish when and why this took place (Sedgwick, 2014). In most instances, a
retrospective study is undertaken when dealing with a group of individuals associated with an
unusual or new treatment/ disease. Essentially, retrospective studies utilize pre-recorded data that

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was gathered and archived for reasons other than research. Nevertheless, it is important to note
that a retrospective study is considerably inferior to a prospective study and should be avoided at
all times in situations where the latter can be conducted (Euser, Zoccali, Jager, & Dekker, 2009).
Issues with Measurement of Exposure and Outcome
With regard to a retrospective study design it is considerably more difficult to establish a
correct metric for assessment of exposure because of the time factor. On the other hand,
measurement of outcome is relatively easier because the subjects are grouped on the basis of
whether or not they express the desired outcome (Todd & Pickard, 2013). In a case-control study
the measurement of exposure is less tasking because the groups are well defined between those
subjects that will be exposed to the treatment and those that will not. Hence, a metric is
formulated that recognizes the change between the two groups of individuals. Similarly, the
outcome in a case control cohort is very easy to quantity or provides a measure for because
distinct differences are expected to be observed between the two groups of participants.
However, the major issue here arises when individuals in both groups exhibit the desired
outcome; thereby creating no defining difference between the two groups of individuals
(Vandenbroucke & Pearce, 2012).
Biasness in Each Study
In a retrospective study design, there are three types of biasness that are commonly
observed: selection, measurement, and length biasness. Selection biasness is largely observed in
retrospective studies where participants have to provide consent for their information to be used
in the experiment. Moreover, when conducting a retrospective study the investigator will attempt
to avoid legal liability or monetary consequences by selecting the most favourable participants.
Length biasness is observed when the exposure duration is considerably long meaning the

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investigator will have to shorten or make the duration considerably more favourable to the
expected runtime of the study. Lastly, measurement biasness relates to the issue of selecting
appropriate measurements for exposure and outcome as discusses in the previous segment
(Norvell, 2010). In the case-control study, it is subject to three types of bias: Observer, recall,
and selection. Observer biasness occurs when the investigator knows the participant's disease
status prior to the interview. Selection biasness takes place when given cases are included in a
study because of the underling characteristics they exhibit that can be directly tied to the risk
factor. Recall biasness occurs when the cases and control individuals recall the exposure
differently than what actually happened (Norvell, 2010).
Analytical Approach
In the case control study the odds ratio (OR) is employed that aids in the establishment of
strength of relationship between the exposure and outcome. The number of groups, power and
alpha that will be used are 3, 80% and 0.05 respectively therefore using G*Power software we
get the sample size of 100 controls and 50 cases. A hypothesis testing approach will be used in
the analysis that will seek to establish the relationship between age and the trough time of
vancomycin. In the retrospective study the data identified for the study will be analyzed for
summary statistics in SPSS version 23. Moreover, a hypothesis t-test will be used to evaluate the
significance in the data with regard to 95% confidence level, and alpha of 0.05. Independence of
variables will be assumed in the assessment.

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References
Euser, A. M., Zoccali, C., Jager, K. J., & Dekker, F. W. (2009). Cohort Studies: Prospective
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Mathijssen, R., Houwing, S., & Brookhuis, K. A. (2009). Case-control studies. In .. Verster, J. G.
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Norvell, D. C. (2010). Study types and bias—Don't judge a study by the abstract's conclusion
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