We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Article |

Longitudinal Aspect of Case-Control Analysis FREE

Emily Vogtmann, MPH; Heather Prentice, MPH; Russell Griffin, MPH; Sandeep Mishra, MPH; Gerald McGwin Jr, MS, PhD
Arch Otolaryngol Head Neck Surg. 2010;136(11):1150. doi:10.1001/archoto.2010.176.
Text Size: A A A
Published online

We recently read with interest the article “Case-Control Analysis of Cochlear Implant Performance in Elderly Patients” by Friedland et al.1 It is our opinion that, despite the title, the study did not use a case-control design because of the longitudinal aspect of the study. Also, patients were not selected according to the outcome of interest, as is the procedure for a case-control study; instead, patients were selected with respect to age, a possible exposure category. The selection criteria suggest that the study actually used a cohort study design, with one-half of the analysis a basic cohort analysis and the other half a matched cohort analysis, with patients matched on duration of deafness and preimplantation Hearing in Noise Test–Quiet (HINT-Q) score.

Because of the matching of younger and older patients, a paired t test should have been used to test for differences in the matched pairs; however, it appears that the 2 groups were inappropriately treated as independent. The authors conclude that there were significant differences by age group in Consonant-Nucleus-Consonant (P = .02) and HINT-Q (P = .02) scores 1 year after implantation; however, analysis using a paired t test for the matched cohort data provided in the table suggested that there were no significant differences by age group in Consonant-Nucleus-Consonant (P = .06) or HINT-Q (P = .07) scores. Therefore, the conclusion that elderly patients should not be expected to have hearing scores as high as those of younger patients with similar characteristics cannot be supported statistically, as the P values exceeded .05 (acknowledging that the absolute differences remained unchanged).

Finally, as with any longitudinal study, it is possible that the results are biased because of a regression toward the mean. If this bias were differential between the older and younger cohorts (eg, younger cohorts were more likely to have extreme measurements of hearing tests in relation to their true mean scores), then both the validity and the interpretation of the results are questionable. The authors should review the literature on the topic of testing and correcting for regression to the mean and determine whether this particular bias is present in their data.

While the results of the current study are questionable for the reasons stated, we hope that the authors take heed of our suggestions and correct the results, accounting for the matched cohort study design. We look forward to seeing the corrected results from this study.


Correspondence: Dr McGwin, Department of Epidemiology, University of Alabama at Birmingham, 1922 Seventh Ave S, Ste K120, Birmingham, AL 35294 (mcgwin@uab.edu).


Friedland  DRRunge-Samuelson  CBaig  HJensen  J Case-control analysis of cochlear implant performance in elderly patients. Arch Otolaryngol Head Neck Surg 2010;136 (5) 432- 438
PubMed Link to Article




Friedland  DRRunge-Samuelson  CBaig  HJensen  J Case-control analysis of cochlear implant performance in elderly patients. Arch Otolaryngol Head Neck Surg 2010;136 (5) 432- 438
PubMed Link to Article


Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Related Content

Customize your page view by dragging & repositioning the boxes below.