HW 8

HW 8

by Elizabeth Black -
Number of replies: 2

Part 1:

1.     Choose a paper describing the development or validation of a measure of relevance in health disparities research (please give the full citation and/or upload the paper if that's possible).

Morisky DE, Ang A, Krousel‐Wood M, Ward HJ. Predictive validity of a medication adherence measure in an outpatient setting. The Journal of Clinical Hypertension. 2008;10(5):348-354.

2.     What was the definition of the construct?

The construct being measured is adherence which is defined as the degree to which a patient follows medical advice.  In this case, the study was specifically looking at the degree to which patients followed their anti-hypertensive medication treatment regimen.

3.     How did the authors provide evidence on the validity of the measure? Could you think of additional approaches to validating the measure?

The investigators compared their novel 8 item adherence scale to an established four item adherence scale using Pearson’s correlation coefficient.  Predictive validity of the scale was assessed through associations with blood pressure levels, knowledge, attitude, social support, stress, comping, and patient satisfaction with clinic visits using confirmatory factor analysis.

4.     How did the authors provide evidence on the reliability of the measure? Could you think of additional approaches to evaluating the reliability of the measure?

To evaluate the reliability of the measure, the authors used multivariate logistic regression analysis to evaluate the odds ratios of various factors associated with medication adherence.  To determine how well the 8-item scale served as a screening tool, sensitivity, specificity, and correct classification rates were estimated.  An additional approach to evaluating the reliability of this measure could be to use it in another patient population (this study was done in Los Angeles) and repeating these measures.

5.     Describe the implications of a lack of measurement validity or reliability for future research applications. 

If this measure is not reliable, it may have an impact on future research into blood pressure control and outcomes.  It is difficult to measure how well a medication works if you can not reliably assess if your study population is adherent.

Part 2:

1.     Find a paper describing a health disparity (please give the full citation or, even better, upload the paper so everyone else can look at it too) 

Patzer RE, Amaral S, Klein M, et al. Racial disparities in pediatric access to kidney transplantation: does socioeconomic status play a role? American Journal of Transplantation. 2012;12(2):369-378.

2.     Summarize the construct and measurement of the dimension of disparity (e.g., racial inequalities?, SES inequalities?) and the outcome measured (e.g., self-rated health).

The construct being measured is racial inequalities to access to transplant and referral for transplantation when socioeconomic factors are adjusted for.

3.     What is the evidence for the validity and reliability of the measures?

The validity of this measure is found in its data set.  Researchers used data from the United States Renal Data System in which all transplant recipients who receive organs in the United States are entered.  This study should essentially capture all pediatric renal transplant patients in the United States in the study period. 

4.      What is the reference category used for the disparity measure (ie, who is the comparison group)? Why does this reference category make sense (or not) for this research question?

The reference category in this case was non-Hispanic white ESRD patients.  This comparison makes sense as this study was specifically examining disparities in access to renal transplantation between non-Hispanic white, white Hispanic, and non-Hispanic black patients.

5.     How is the disparity quantified or measured?  Is this an absolute or relative measure or are both provided?  Describe which type of measure you would prefer for this research area, or, if both, why. 

The disparity is presented as a hazard ratio with the hazard being renal transplantation.  This is a relative measure as it is compared to the hazard of transplantation among non-Hispanic white patients.  This is an appropriate measure to use because the study is specifically interested in disparities between non-Hispanic white ESRD patients and non-Hispanic black and Hispanic ESRD patients.


In reply to Elizabeth Black

Re: HW 8

by Aksharananda Rambachan -
Medication adherence is a challenging construct. I wonder if there has been any biological markers of adherence to hypertension medications (or if this is needed) and how it would compare to these questionnaires. Another validation metric would be to count the pills taken or the newer pill counting technologies for adherence.
In reply to Elizabeth Black

Re: HW 8

by Mohammad Fallahzadeh Abarghouei -
In Part 1, Elizabeth discusses different aspects of an article that evaluates the predictive validity of measure of adherence in outpatient setting with focus on adherence to antihypertensive medications. To validate their findings, the authors of this paper compared their results with an already validated measure of medication adherence. I think additional more robust ways of validation can include using home blood pressure monitoring and evaluating the variation in blood pressure measurements which can indicate medication non-adherence; comparing the results of the survey being evaluated with more objective measures of medication adherence like periodically checking urine levels of antihypertensive medications (this is a novel developing method for evaluation of antihypertensive medication adherence).