Diabetes Systematic Review (of Therapy)

Diabetes

SYSTEMATIC REVIEW (OF THERAPY) WORKSHEET

Madden, S., Loeb, S. Smith, C. (2008). An integrative literature review of lifestyle interventions for the prevention of type II diabetes mellitus. Journal of Clinical Nursing. 17 (1): 2243-56.

Are the results of this systematic review valid?

Is this a systematic review of randomised trials?

Yes, but small # of participants due to study nature; results extrapolated.

Does it include a methods section that describes:

a) finding and including all relevant trials?

b) assessing their individual validity?

Yes, methods described and validity discussed (see pages 2245-7.

Were the results consistent from study to study?

Yes, statistically consistent.

Were the individual patient data used in the analysis (or aggregate data)?

Aggregate data

Are the valid results of this systematic review important?

Yes. Systematic reviews of the effects of diet on Type II diabetes are important in that it can be translated out to a wide variety of patient concerns and actual needed interventions. The point of the research was to show that the patient can be participative in a number of interventions (diet and exercise predominantely) that will have a major impact on the manifesting symptoms of Type II diabetes. The authors concende that their major limitation was that their data base searches were limited to the three most relevant databases, and that a larger, more longitudinal study should be funded to validate the data set and suggested outcomes.

Translating odds ratios to NNTs:

The numbers in the body of the tables are the NNTs for the corresponding odds ratio at that particular patient's expected event rate (PEER).

1. When the odds ratio (OR) < 1

This table applies when a bad outcome is prevented by therapy.

OR < 1

0.9

0.8

0.7

0.6

0.5

Patient's expected event rate (PEER)

0.05

2.09a

69

52

41b

0.10

54

36

27

21

0.20

61

30

20

14

11

0.30

46

22

14

10

8

0.40

40

19

12

9

7

0.50

38

18

11

8

6

0.70

44

20

13

9

6

0.90

101c

46

27

18

12d

a The relative risk reduction (RRR) here is 10%

b The RRR here is 49%

c For any OR, NNT is lowest when PEER = 0.50

d The RRR here is 9%

2. When the odds ratio (OR) > 1

This table applies both when a good outcome is increased by therapy and when a side-effect is caused by therapy.

OR > 1

1.1

1.2

1.3

1.4

1.5

Patient's expected event rate (PEER)

0.05

71

54

43

0.10

57

38

29

23

0.20

64

33

22

17

14

0.30

49

25

17

13

11

0.40

43

23

16

12

10

0.50

42

22

15

12

10

0.70

51

27

19

15

13

0.90

66

47

38

32

Can you apply this valid, important evidence from a systematic review in caring for your patient?

Do these results apply to our patient?

Is your patient so different from those in the study that its results cannot apply?

No, the majority of the patients who are diagnosed with Type II diabetes are indicative of the patient issues in the study. In fact, most fall well within the parameters of the study potential, which also validates the data set.

Is the treatment feasible in your setting?

Completely, 100%. Exercise and diet are relatively easy attributes to change, particularly with data showing how these changes can influence amounts of medication and quality of life.

What are your patient's potential benefits and harms from the therapy?

Method I: In the OR tables above, find the intersection of the closest odds ratio from the systematic review and your patient's expected event rate (PEER)

Because this is a natural intervention (exercise and diet); almost all the patient's will show some benefit from the introduction of more exercise and limited diet. PEER issues depend on the severity of the symptoms for individual patients. Most likely scenario based on the data: 42-49

Method II: To calculate the NNT from any OR and PEER:

-2 risk ratio; very little risk in using diet and exercise to mitigate diabetes conditions. (see: http://www.cebm.net/index.aspx?o=1044)

Are your patient's values and preferences satisfied by the regimen and its consequences?

Do you and you patient have a clear assessment of their values and preferences?

Yes, it is clear that increasing moderate levels of aerobic exercise, parituclarly walking, jogging, swimming or biking; coupled with a healthier diet (more fresh vegetables, low glycemic fruits, low refined sugars and processed flours, etc.) will have a positive effect on type II diabetes measurement.