Table 2.
Health Literacy and Outcomes in Diabetes: Strength of Evidence and Summary of Findings
| Category | Outcome | Total # of studies by study design = N (# of studies NOT controlling for confounding = n1; # of studies controlling for confounding = n2) | Summary of results | Strength of evidence | ||||
|---|---|---|---|---|---|---|---|---|
| Studies NOT controlling for confounding (n1) | Studies controlling for confounding (n2) | |||||||
| Design | N (n1; n2) | Positive results* | Negative results† | Positive results* | Negative results† | |||
| Clinical outcomes | A1c | Cross-sectional | 12 (4; 8) | 1 | 3 | 4 | 4 | Insufficient |
| Longitudinal | 1 (0; 1) | – | – | – | 1 | |||
| Low-density lipoprotein (LDL) | Cross-sectional | 1 (0; 1) | – | – | – | 1 | Low | |
| Blood pressure | Cross-sectional | 2 (1; 1) | – | 1 | – | 1 | Low | |
| Self-reported significant hypoglycemia | Cross-sectional | 1 (0; 1) | – | – | 1 | – | Low | |
| Self-reported complications | Cross-sectional | 2 (0; 2) | 1 | – | – | 1 | Insufficient | |
| Achievement of clinical outcome goals for A1c | Longitudinal | 1 (0; 1) | – | – | 1 | – | Low | |
| Behavioral outcomes | Self-care | Cross-sectional | 4 (0; 4) | – | – | 4 | – | Moderate |
| Self-monitoring of blood glucose | Cross-sectional | 1 (0; 1) | – | – | – | 1 | Low | |
| Self-efficacy | Cross-sectional | 5 (1; 4) | 1 | – | 1 | 3 | Insufficient | |
| Self-management support | Cross-sectional | 1 (0; 1) | – | – | 1 | – | Low | |
| Medication adherence | Cross-sectional | 1 (0; 1) | – | – | – | 1 | Low | |
| Diabetes knowledge | Cross-sectional | 8 (3; 5) | 3 | – | 5 | – | High | |
| Longitudinal | 1 (0; 1) | – | – | 1 | – | |||
| Patient-provider interaction | Patient–physician communication | Cross-sectional | 2 (1; 1) | 1 | – | 1 | – | Low |
| Information exchange | Cross-sectional | 1 (0; 1) | – | – | 1 | – | Low | |
| Involvement in decision making | Cross-sectional | 1 (1: 0) | 1 | – | – | – | Insufficient | |
| Trust | Cross-sectional | 2 (1; 1) | – | 1 | 1 | – | Insufficient | |
| Other outcomes | Prevalence of heart failure | Cross-sectional | 1 (0; 1) | – | – | – | 1 | Low |
| Prevalence of depressive symptoms | Cross-sectional | 1 (0; 1) | – | – | – | 1 | Low | |
| Health-related quality of life | Cross-sectional | 1 (1; 0) | – | 1 | – | – | Insufficient | |
| Diabetes health-related beliefs | Cross-sectional | 1 (0; 1) | – | – | – | 1 | Low | |
| Medication beliefs | Cross-sectional | 1 (0; 1) | – | – | 1 | – | Low | |
| Healthcare and general discrimination | Cross-sectional | 1 (0; 1) | – | – | 1 | – | Low | |
| Use of computers and internet | Cross-sectional | 2 (1; 1) | 1 | – | 1 | – | Low | |
*Indicates that the study found a significant association between health literacy level and the outcomes
†Indicates that the study did not find a significant association between health literacy level and the outcomes