Table 2.
The psychometric properties of the DHL instrument
| Difficulty factor | Corrected Item-total correlation | Cronbach's α if item is deleted | Test retest reliability | |||
|---|---|---|---|---|---|---|
| Domain | Item | p-valuet‡ | ||||
| 1. | Diabetes occurs in people with insufficient or no insulin# | 0.81 | 0.406 | 0.780 | 0.508 | |
| 2. | Diabetes can be cured after taking medicines for a period of time | 0.79 | 0.458 | 0.777 | 0.791 | |
| 3. | As long as a diabetic person's fasting blood sugar level in the person's fasti morning is in the normal range, he/she can eat anything for that day | 0.88 | 0.377 | 0.782 | 0.453 | |
| 4. | If the blood sugar level is high for long period of time, it may cause other health problems such as blindness# | 0.92 | 0.340 | 0.784 | 1.000 | |
| Diabetes | 5. | Normal fasting blood sugar is between 4 to 6 mmol/L# | 0.90 | 0.128 | 0.791 | 0.453 |
| 6. | There is no problem for our blood pressure to remain high as long as we do not feel sick | 0.73 | 0.548 | 0.771 | 0.125 | |
| 7. | Blood pressure of 140/90 mmHg and above is considered as high# | 0.78 | 0.190 | 0.790 | 0.791 | |
| 8. | If not treated, high blood pressure can lead to kidney damage# | 0.70 | 0.378 | 0.781 | 0.180 | |
| 9. | We can feel whether our blood pressure is high or not | 0.23 | 0.125 | 0.794 | 0.189 | |
| Hypertension | 10. | High blood pressure can be caused by hardened or narrowed blood vessels due to fatty deposits# | 0.78 | 0.270 | 0.786 | 1.000 |
| 11. | LDL cholesterol is known as "good" cholesterol | 0.14 | 0.209 | 0.789 | 1,000 | |
| 12. | High level of "bad" cholesterol blocks blood vessels the risk of a heart attack# | 0.86 | 0.252 | 0.787 | 0.453 | |
| Hyperlipidaemia | 13. | High level of "bad" cholesterol" can also occur in thin people# | 0.86 | 0.381 | 0.781 | 1.000 |
| 14. | Cholesterol is present in some food and also produced in our liver# | 0.69 | 0.267 | 0.787 | 0.238 | |
| 15. | Omega-3 supplements can reduce "bad" cholesterol more than the medicine given by the doctor | 0.29 | 0.377 | 0.781 | 0.019* | |
| 16. | We can stop taking medicine(s) once our blood sugar/blood pressure is well controlled. | 0.81 | 0.450 | 0.777 | 0.109 | |
| 17. | All medicines must be taken after meals only | 0.74 | 0.179 | 0.791 | 0.508 | |
| 18. | If someone misses taking his/her medicine, he/she can take double the amount for the next dose | 0.92 | 0.518 | 0.779 | 0.375 | |
| 19. | People with type 1 diabetes cannot depend on tablets or oral type of medicines to control their blood sugar# | 0.42 | 0.157 | 0.794 | 0.011* | |
| 20. | All medicines for diabetes are the same, so we can share them if we have diabetes | 0.88 | 0.273 | 0.786 | 0.727 | |
| 21. | Medicines for diabetes or high blood pressure can be taken on alternate days to reduce side effects | 0.84 | 0.383 | 0.781 | 1.000 | |
| 22. | Medicine for reducing cholesterol only has to be taken just before taking any oily or fatty foods | 0.83 | 0.354 | 0.782 | 1.000 | |
| Medication | 23. | All medicines must be stored in the refrigerator | 0.90 | 0.396 | 0.781 | 0.388 |
| 24. | Tobacco smoking increases risk of heart diseases# | 0.90 | 0.385 | 0.782 | 0.125 | |
| 25. | If you do not take any white sugar, you will not have enough energy | 0.81 | 0.355 | 0.782 | 0.549 | |
| 26. | Vegetable oils do not contain cholesterol, therefore they are safe to be taken in large amount | 0.75 | 0.311 | 0.784 | 1.000 | |
| 27. | 30 minutes of exercise per week is enough to reduce the risk of getting heart problems | 0.78 | 0.233 | 0.788 | 0.424 | |
| General Issues | 28. | Diabetic people can eat as much fruits (such as banana, papaya, orange, water melon) as they like | 0.90 | 0.065 | 0.794 | 0.062 |
#Statements are true
‡Test-retest reliability on the individual (dichotomous) items was conducted using the McNemar's test (binomial distribution was used)
*Statistically significant at p < 0.05