Ophthalmology Study Design Worksheet #7
Cohort Study
Cohort Study. An observational study that begins by identifying individuals with (study group) and without (control group) a factor being investigated; study and control groups may be concurrent or non concurrent.
Manuscript #: __________________
(For Office Use)		  
First Author's Name: ______________________________________________________
Manuscript Title: ______________________________________________________  
Heading Descriptor Yes/No Page/¶ N/A Comments
Title: 1. Manuscript content clarified within 135 character limit. ________ ________ ________ ________
Abstract: 2. Structured per Instructions for Authors. ________ ________ ________ ________
  3. Design identified as Cohort Study. ________ ________ ________ ________
  4. Population under study defined and issue(s) of interest clarified. ________ ________ ________ ________
Introduction:
 5. Statement/clarification of the research question/objectives. ________ ________ ________ ________
  6. Background for why study was conducted. ________ ________ ________ ________
7. Brief review of pertinent literature. ________ ________ ________ ________
Methods: 8. Define the exposure variable(s) that is/are being assessed and indicate how they were measured. ________ ________ ________ ________
9. Define the source of patients (record review, incoming patients, specialty practice, etc.) or reference previous publication(s). (Applies to items #9-15). ________ ________ ________ ________
  10. List inclusion and exclusion criteria. ________ ________ ________ ________
  11. Indicate time period used for identifying patients. ________ ________ ________ ________
  12. Clarify sample size determination (e.g., statistically or cases accrued over a specified time period); if statistically pre determined, elaborate in statistical methods section. ________ ________ ________ ________
  13. Indicate whether or not subjects were consecutive. ________ ________ ________ ________
14. Indicate whether or not inclusion was dependant on completion of a specified follow-up. ________ ________ ________ ________
  15. Provide time period for accrual of subjects and indicate whether they were accumulated prospectively or retrospectively. ________ ________ ________ ________
  16. Indicate if evaluators of subjective components of eligibility were masked to the status of the participants. ________ ________ ________ ________
  17. Document IRB approval and informed consent. ________ ________ ________ ________
  18. Describe relevant primary and secondary outcome measures and the time point used for outcome determination when important. ________ ________ ________ ________
19. Indicate how outcome assessments were made and define evaluators. ________ ________ ________ ________

(Follow up Issues)
  20. Describe follow up schedule if standardized or describe the frequency of outcome assessment and how the timing of assessment was determined. ________ ________ ________ ________
  21. Describe the length of follow-up. ________ ________ ________ ________
  22. Describe efforts to maintain follow-up and efforts to ascertain completeness of follow-up. ________ ________ ________ ________

(Statistical Issues/Data Management)
  23. Clarify any assumptions used in calculating sample size. ________ ________ ________ ________
24. Indicate how data were extracted for analysis (e.g., chart review, or prospectively completed data forms). ________ ________ ________ ________
  25. Explain any patient exclusions from analysis. ________ ________ ________ ________
  26. Explain analytic method for all outcome analyses and identify specific software programs employed. ________ ________ ________ ________
  27. Describe how confounding was assessed and/or controlled. ________ ________ ________ ________
  28. If applicable, explain how missing data were handled in the analysis. ________ ________ ________ ________
Results:
 29. Describe demographic characteristics and all variables of prognostic importance. ________ ________ ________ ________
  30. Summarize completeness of follow-up. Clarify what follow-up was expected and the percentage of patients for which incomplete follow-up was obtained. Reasons for incomplete follow-up (death, lost to follow-up, non interpretable data) should be provided. ________ ________ ________ ________
  31. If the primary outcome assessment is at a fixed time point, provide the absolute number and percentage of patients completing the assessment. ________ ________ ________ ________
  32. If the outcome assessment is at several time points, provide the absolute number and percentage of participants who completed the assessment at each time point. ________ ________ ________ ________
  33. Compare completeness of follow-up within each subgroup for each candidate risk factor of interest. ________ ________ ________ ________
34. Provide an estimate of risk (e.g., relative risk, relative hazard, or differences in means for continuous outcome measures) and a measure of precision (standard devia-
tion, confidence interval, etc.) for differences between groups of patients.		 ________ ________ ________ ________
  35. Report results of other statistical comparisons made of the subgroups of candidate risk factors. ________ ________ ________ ________
  36. Provide both absolute numbers and percentages when feasible (e.g., 33 of 50 eyes, 66%). ________ ________ ________ ________
  37. Provide P values for all major comparisons. ________ ________ ________ ________
  38. Report assessment of confounding among the known and candidate risk factors. ________ ________ ________ ________
Discussion:
 39. Summarize important study findings. ________ ________ ________ ________
  40. Interpret the study findings. ________ ________ ________ ________
  41. Discuss possible bias. ________ ________ ________ ________
  42. Discuss how imbalance in the distribution of strong predictors of outcome might have influenced relationships under study. ________ ________ ________ ________
  43. Assess the possibility that chance accounts for any statistically significant differences between groups. ________ ________ ________ ________
  44. If "no difference" is reported, provide the power to detect a difference of meaningful clinical magnitude. ________ ________ ________ ________
  45. When applicable, discuss the biological plausibility of findings. ________ ________ ________ ________
  46. Contrast or compare study results to other studies. ________ ________ ________ ________
  47. Comment on generalizability of results and identify non applicable patients. ________ ________ ________ ________
  48. Summarize study conclusions and study design limitations. ________ ________ ________ ________
  49. When indicated, summarize the applicability of results to clinical practice. ________ ________ ________ ________
  50. Comment on future desirable studies when indicated. ________ ________ ________ ________



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          Copyright © 2003 by the American Academy of Ophthalmology.