Table 1.
Summary of characteristics of the included studies.
| References/country/study design | Sample | Diabetes | Diabetic retinopathy evaluation | Periodontal evaluation | Statistical analysis | Results | ||
|---|---|---|---|---|---|---|---|---|
| Sample size (n) | Mean age | Type (mean time since diagnosis in years) | Diagnostic technique | |||||
| Veena et al. (11) India Cs |
G1: Mild to moderate non-PDR: 55 G2: Moderate to severe non-PDR: 44 G3: PDR: 52 G4: Control group: 49 |
– | 2 | HbA1c test | Eye examination (unspecified) | PI, GI, PPD, and CAL. | ANOVA one-way with Tukey's post hoc test; Student's T-test | A statistically significant correlation between the severity of DR and the severity of periodontitis was found (p < 0.001) |
| Song et al. (16) Korea Cs |
Diabetics (1.138) Diabetics with DR: 90 Diabetics without DR: 468 |
Diabetics with DR: 58.5 ± 1.6 Diabetics without DR: 57 ± 0.7 |
2 (With RD: 10.9 ± 1.0) (Without RD: 4.7 ± 0.3) |
HbA1ctest | Nonmydriatic fundus photography (TRC-NW6S; Topcon, Tokyo, Japan) | CPI | Multiple logistic regression | The risk of DR was positively associated with the presence of periodontitis in non-obese diabetic |
| Amiri et al. (17) Iran Cs |
Diabetics with DR: 84 Diabetics without DR: 129 |
– | 2 | HbA1c test | Fundus examination by a trained ophthalmologist | PI, CPI, PPD, and CAL | Multivariable logistic regression | The severity of periodontitis was significantly correlated with the severity of DR (p < 0.011) |
| Ota et al. (18) Japan Cs |
Diabetics with PDR: 7 Diabetics with pre-PDR: 9 Diabetics without DR: 7 |
55.4 ± 11.3 | 2 (10.3 ± 8.8) | HbA1c test | Eye examination (unspecified) | Number of teeth present, PPD, BOP, and tooth mobility | Chi-square test | The average of patients with severe periodontitis (SD ± 7 mm) was significantly higher in patients with DR |
| Karjalainen et al. (19) Finland Cs |
Diabetics with DR: 11 Diabetics without DR: 4 |
Male: 30.9 ± 2.7 Female: 29.6 ± 2.1 |
1 | All information was collected from patient records | Direct and indirect ophthalmoscopy. Fundus photographies were taken | PI, PPD, CAL, and BOP | Chi-square test | Differences were significant (P = 0.05) between the groups with and without DR. The severity of periodontitis increased with the severity of DR. |
G1, Group 1; G2, Group 2; G3, Group 3; DR, diabetic retinopathy; PDR, proliferative diabetic retinopathy; HbA1c, glycated hemoglobin; Cs, cross-sectional study; PI, plaque index; GI, gingival index; PPD, probing pocket depth; CAL, clinical attachment level; BOP, bleeding of probing; CPI, community periodontal index.