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FY 2008 Audit Instructions

5. PERFORMING A MANUAL AUDIT

a. Sample Size Calculations

For manual auditors, the time requirements of the chart review process generally make it impractical to review all active DM patients. Rather than reviewing all records, a random sample of records may be selected for review. The number of charts you need to select depends on the number of active patients in your diabetes register.

Table 1 outlines the minimum number of charts you will need to audit to be reasonably sure (90% confident) that a 10% difference noted from a previous or subsequent audit is a real change and not just due to chance. If, for example, your facility has 1000 active patients with diabetes, you will need to audit a total of 63 charts.

Table 1 - Sample Size Calculations (see explanation below table)

Sample size needed to be 90% or 95% certain that the rate you find is within 10% or within 5% of the true rate, for populations up to 4000.

Population	╒══ 90% Certainty══╕		╒═95% Certainty ═╕
(# of DM Patients)	Within 10%	Within 5%	Within 10%>	Within 5%
<30	all	all	all	all
30	21	27	23	28
40	25	35	28	36
50	29	42	33	44
60	32	49	37	52
70	34	56	40	59
80	37	62	44	66
90	39	68	46	73
100	40	73	49	79
110	42	78	51	86
120	43	83	53	91
130	44	88	55	97
140	46	92	57	103
150	47	96	59	108
160	48	101	60	113
170	48	104	61	118
180	49	108	63	123
190	50	112	64	127
200	51	115	65	132
220	52	121	67	140
240	53	127	69	148
260	54	133	70	155
280	54	138	72	162
300	55	142	73	168
320	56	147	74	175
340	56	151	75	180
360	57	154	76	186
380	57	158	77	191
400	58	161	77	196
420	58	165	78	201
440	59	168	79	205
460	59	170	79	209
480	59	173	80	213
500	60	176	81	217
525	60	179	81	222
550	60	181	82	226
575	61	184	82	230
600	61	186	83	234
650	61	191	84	241
700	62	195	84	248
750	62	199	85	254
800	62	202	86	260
900	62	208	87	269
1000	63	213	88	278
2000	65	238	92	322
3000	66	248	93	341
4000	67	253	94	350
	▲ Minimum number of charts recommended

The diabetes register will often include people who are not considered active patients of the clinic and thus do not need to be audited. These charts should be identified early in the audit process and excluded. Table 2 outlines the charts which are to be included and excluded.

Table 2 - Patients to Include and Exclude in the Chart Audit

Include patients who:

· Attend regular clinics or diabetes clinics.

· Sometimes refuse care or have special motivational problems (e.g., alcoholism).

· Are not attending clinic, but you do not know if they have moved or have found another source of care.

Exclude patients who:

· Have not had at least one primary care visit during the past 12 months.

· Receive primarily referral or contract care, paid by IHS.

· Have arranged other MD care, paid with non-IHS monies.

· Receive their primary care at another IHS or Tribal health facility.

· Live in a jail, and receive care there.

· Live in a nursing home, and receive care there.

· Attend a dialysis unit (if on-site dialysis not available).

· Have gestational diabetes.

· Have prediabetes (IFG or IGT) only.

· Have moved -- permanently or temporarily (should be documented)

· You are unable to contact, defined as 3 tries in 12 months (should be documented in the chart).

· Have died.

Keep in mind that unless your diabetes register is frequently updated, up to 10% of the people in the diabetes registry may not qualify to be included in the audit. To make sure you have an adequate sample at the end of the audit, increase the chart sample by at least 10%. In the example of 63 charts used above, this would mean an additional 6 charts, or a total of 69, would need to be pulled for the audit.

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