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• Risk of cataract for patients with diabetes mellitus
  Tomoyuki Kawada
  Published on: 24 October 2012

• Published on: 24 October 2012

  Risk of cataract for patients with diabetes mellitus

  • Tomoyuki Kawada, Professor

  I read the paper entitled "Risk of selected eye diseases in people admitted to hospital for hypertension or diabetes mellitus: record linkage studies" with interest. It elucidated that diabetes mellitus has a risk of several ocular diseases with significance using two big epidemiological data. However, I have two queries on their outcome by selecting the association between cataract and diabetes mellitus.

  First,...

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  I read the paper entitled "Risk of selected eye diseases in people admitted to hospital for hypertension or diabetes mellitus: record linkage studies" with interest. It elucidated that diabetes mellitus has a risk of several ocular diseases with significance using two big epidemiological data. However, I have two queries on their outcome by selecting the association between cataract and diabetes mellitus.

  First, Goldacre et al. described rate ratios concerning several eye diseases caused by hypertension or diabetes mellitus. For example, risk of cataract in diabetes was high presenting rate ratio (95% confidence interval) of 2.95 (2.75 to 3.16) and 2.30 (2.24 to 2.35) in their two epidemiological datasets (1). Although sex, age, year of admission and patients' area of residence was adjusted by matching procedure, their outcome is a hospital-based case control study with no specification on the type of cataract. Mukesh et al. conducted a follow-up study, and diabetes mellitus and having taken calcium channel blockers for longer than 5 years were independent risk factors for posterior subcapsular cataract (2), presenting hazard ratio (95% confidence interval) of 2.9 (1.7-5.1) and 2.9 (1.2-6.9), respectively. In addition, hazard ratio (95% confidence interval) of age by one year increase for posterior subcapsular cataract was 1.09 (1.07-1.1) (2). Effect of confounding variables on the association between cataract and diabetes mellitus are more understandable in cohort study compared with case-control study as mentioned above.

  Second, Goldacre et al. described the study limitation for the lack of information on the clinical state of diabetes mellitus including treatment (1). The information on the clinical state of diabetes mellitus is useful in combination with diabetic retinopathy.

  The hospital-based case control study has a merit of satisfactory statistical power, and further study on the association between cataract and diabetes mellitus should be conducted including the above mentioned information.

  References

  1. Goldacre MJ, Wotton CJ, Keenan TD. Risk of selected eye diseases in people admitted to hospital for hypertension or diabetes mellitus: record linkage studies. Br J Ophthalmol 2012;96:872-6.

  2. Mukesh BN, Le A, Dimitrov PN, et al. Development of cataract and associated risk factors: the Visual Impairment Project. Arch Ophthalmol 2006;124:79-85.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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