Background
Methods
Setting
Objects
Selection of cases
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Step 1: Encode all HAI cases obtained from the current prevalence survey;
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Step 2: Divide the total number of HAI cases by 10 to get the sampling interval;
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Step 3: Use the last few digits of a randomly drawn RMB currency to determine the first case. The selection principle of these digits was that the number to be taken was the maximum number but not greater than the sampling interval;
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Step 4: Select the second case by taking the number of first case plus the sampling interval; and so on, select all cases of HAI.
Selection of controls
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① Select patients in the same ward with HAI cases;
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② In the present prevalence survey, the patients without HAI were selected;
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③ It was necessary to eliminate the confounding bias of pre-infection time. So the total length of hospitalization stay before ‘matching day’ (Interval between the ‘matching day’ and the admission date) of the selected controls should be longer than or equal that of the HAI cases before infection (Interval between the infections date and admission date);
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④ Select the patient with the same gender and in the same age group as the cases, and the age difference should be within 5 years as far as possible; The control of infant case aged <1 year should be the infant aged <1 year;
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⑤ The following status of control need to be consistent with the case: whether there was community acquired infections at the time of admission, whether to be hospitalized for 2 times in a year, whether there were tumors, AIDS, malnutrition and other low immune function.
Score | Classification basis |
---|---|
1 | Routine observation was required and care and treatment were not required (including patients who need to be observed after surgery). |
2 | Stable condition, but preventive observation is needed, it is not necessary to strengthen care and treatment of patients, for example, some patients for whom myocarditis, myocardial infarction need to be excluded and overnight observation is needed after taking medicine. |
3 | Stable condition, but care and/or guardianship of patients need to be strengthened, such as coma patients or patients with chronic renal failure. |
4 | Unstable conditions, increased care and treatment are needed, and regular evaluation and adjustment of treatment programmes are needed, such as arrhythmia, diabetic ketoacidosis patients (but no coma, shock, DIC). |
5 | Unstable conditions, in a coma or shock state, cardiopulmonary resuscitation is needed or nursing care needs to be strengthened, and the care and treatment of patients need to be evaluated. |
Confounders
Variable | Value |
---|---|
Area (classified by GDP) | |
Chengdu | 1 |
Mianyang, Deyang, Yibin, Nanchong, Luzhou, Dazhou, Leshan, Liangshan | 2 |
Panzhihua, Suining, Meishan, Guang’ an, Neijiang, Zigong | 3 |
Ziyang, Guangyuan, Ya’ an,Bazhong, Aba, Ganzi | 4 |
Number of hospital beds | |
< 300 | 1 |
300 ≤ and < 500 | 2 |
500 ≤ and < 800 | 3 |
≥ 800 | 4 |
Calculation of costs
Statistical analysis
Results
Patient inclusion
Characteristics of patients
Variable | Number of Hospitals (n = 51) | Number of Pairs (n = 175) | Ratio of composition |
---|---|---|---|
Classification of GDP | |||
1 | 4 | 19 | 10.86% |
2 | 23 | 71 | 40.57% |
3 | 11 | 37 | 21.14% |
4 | 13 | 48 | 27.43% |
Classification of the number of hospital beds | |||
1 | 19 | 29 | 16.57% |
2 | 11 | 47 | 26.86% |
3 | 13 | 49 | 28.00% |
4 | 8 | 50 | 28.57% |
Variable | Cases(n = 175) | Controls(n = 175) |
---|---|---|
Mean age ± SD | 58.15 ± 20.56 | 57.76 ± 20.09 |
Classification score of disease conditions | ||
1 | 40(22.9%) | 40(22.9%) |
2 | 63(36.0%) | 63(36.0%) |
3 | 42(24.0%) | 42(24.0%) |
4 | 26(14.9%) | 26(14.9%) |
5 | 4(2.3%) | 4(2.3%) |
Gender | ||
Male | 99(56.6%) | 99(56.6%) |
Female | 76(43.4%) | 76(43.4%) |
Community infections | 39(22.3%) | 39(22.3%) |
Repeated hospitalization | 41(23.4%) | 41(23.4%) |
Low immune function | 29(16.6%) | 29(16.6%) |
Overall analysis
Stratified analysis
Variable | Number of Pairs (n = 175) | Difference of length of stay in pairs Median (range) | Statistics (Z) |
P
|
---|---|---|---|---|
Classification of the number of hospital beds | ||||
1 | 29 | 4.0(−8~ 107) | 3.136 | 0.002 |
2 | 47 | 4.0(−30~ 52) | 2.131 | 0.033 |
3 | 49 | 6.0(−56~ 134) | 2.716 | 0.005 |
4 | 50 | 6.0(−94~ 52) | 2.045 | 0.041 |
Classification of GDP | ||||
1 | 19 | 5.0(−23~ 69) | 2.439 | 0.015 |
2 | 71 | 3.0(−94~ 134) | 1.712 | 0.087 |
3 | 37 | 4.0(−30~ 88) | 2.106 | 0.035 |
4 | 48 | 7.0(−39~ 107) | 3.847 | 0.000 |
HAIs sites | ||||
Upper respiratory | 23 | 3.0(−21~ 14) | − 2.236 | 0.026 |
Blood related | 5 | 6.0(−22~ 20) | −0.135 | 0.893 |
Superficial incision | 20 | 10.0(−3~ 107) | −3.680 | 0.000 |
Organ lacunar | 2 | 4.5(3~ 6) | −1.342 | 0.180 |
Deep incision | 6 | 12.0(−10~ 52) | − 1.802 | 0.072 |
Intra-abdominal tissue | 1 | 5.0(5~ 5) | / | / |
Urinary | 23 | 6.0(−13~ 88) | −2.480 | 0.013 |
Skin soft-tissue | 12 | 1.0(−14~ 32) | 0.157 | 0.875 |
Lower respiratory | 76 | 5.0(−94~ 134) | −2.439 | 0.015 |
Gastrointestinal | 6 | 1.0(−22~ 54) | −0.674 | 0.500 |
Other | 1 | 11.0(11~ 11) | / | / |
Variable | Number of Pairs (n = 175) | Difference of costs in pairs Median (range) | Statistics (Z) |
P
|
---|---|---|---|---|
Classification of the number of hospital beds | ||||
1 | 29 | 133.06(− 986.46~ 7891.43) | 2.983 | 0.003 |
2 | 47 | 194.23(− 1163.39~ 8198.11) | 2.106 | 0.035 |
3 | 49 | 748.94(− 2815.11~ 25,447.11) | 4.491 | 0.000 |
4 | 50 | 572.45(− 6589.03~ 31,153.30) | 2.106 | 0.035 |
Classification of GDP | ||||
1 | 19 | 1362.03(− 270.13~ 25,447.11) | 3.662 | 0.000 |
2 | 71 | 477.72(− 1632.29~ 31,153.30) | 4.111 | 0.000 |
3 | 37 | 230.68(−6589.03~ 6712.01) | 2.195 | 0.028 |
4 | 48 | 253.22(−2815.11~ 9800.81) | 2.913 | 0.004 |
HAIs sites | ||||
Upper respiratory | 23 | 69.08(−986.46~ 761.57) | −1.186 | 0.236 |
Blood related | 5 | 1163.39(390.33~ 1578.86) | −2.023 | 0.043 |
Superficial incision | 20 | 574.77(− 1117.95~ 25,447.11) | −3.136 | 0.002 |
Organ lacunar | 2 | 685.30(283.52~ 1087.09) | −1.342 | 0.180 |
Deep incision | 6 | 1406.22(399.98~ 3431.36) | −2.201 | 0.028 |
Intra-abdominal tissue | 1 | 2086.92(2086.92~ 2086.92) | / | / |
Urinary | 23 | 330.14(−6589.03~ 6712.01) | −2.201 | 0.043 |
Skin soft-tissue | 12 | 39.06(−789.99~ 4542.83) | −0.078 | 0.937 |
Lower respiratory | 76 | 993.88(− 6064.87~ 31,153.30) | −5.486 | 0.000 |
Gastrointestinal | 6 | 51.63(−12.32~ 5168.36) | − 1.992 | 0.046 |
Other | 1 | 335.81(335.81~ 335.81) | / | / |
Multiple linear regression analysis
Variable | Unstandardized Coefficients | Std. Error | Standardized Coefficients | Statistics (t) |
P
|
---|---|---|---|---|---|
Constant | 3.820 | .120 | 31.944 | .000 | |
HAIs sites | |||||
Blood related | .762 | .208 | .265 | 3.661 | .000 |
Superficial incision | .482 | .128 | .320 | 3.760 | .000 |
Organ lacunar | .673 | .308 | .149 | 2.184 | .030 |
Deep incision | .774 | .195 | .294 | 3.961 | .000 |
Intra-abdominal tissue | .695 | .435 | .109 | 1.595 | .113 |
Urinary | .511 | .124 | .360 | 4.120 | .000 |
Skin soft-tissue | .422 | .151 | .222 | 2.789 | .006 |
Lower respiratory | .606 | .104 | .625 | 5.820 | .000 |
Gastrointestinal | .060 | .190 | .023 | .315 | .753 |
Other | −.049 | .429 | −.008 | −.114 | .909 |
Classification of GDP | |||||
1 | .088 | .124 | .057 | .710 | .479 |
2 | −.052 | .081 | −.053 | −.649 | .517 |
3 | −.076 | .096 | −.064 | −.784 | .434 |
Classification of the number of hospital beds | |||||
1 | −.241 | .102 | −.184 | −2.367 | .019 |
2 | −.162 | .090 | −.149 | −1.795 | .075 |
3 | .013 | .097 | .012 | .138 | .890 |
Variable | Unstandardized Coefficients | Std. Error | Standardized Coefficients | Statistics (t) |
P
|
---|---|---|---|---|---|
Constant | 1.269 | .087 | 14.533 | .000 | |
HAIs sites | |||||
Blood related | .315 | .152 | .162 | 2.077 | .039 |
Superficial incision | .305 | .093 | .299 | 3.261 | .001 |
Organ lacunar | .070 | .224 | .023 | .314 | .754 |
Deep incision | .579 | .142 | .326 | 4.066 | .000 |
Intra-abdominal tissue | .184 | .317 | .043 | .580 | .563 |
Urinary | .288 | .090 | .301 | 3.198 | .002 |
Skin soft-tissue | .135 | .117 | .097 | 1.153 | .251 |
Lower respiratory | .211 | .076 | .319 | 2.769 | .006 |
Gastrointestinal | .041 | .138 | .023 | .298 | .766 |
Other | .278 | .312 | .065 | .891 | .374 |
Classification of GDP | |||||
1 | −.028 | .090 | −.027 | −.314 | .754 |
2 | −.094 | .059 | −.140 | −1.586 | .115 |
3 | −.083 | .070 | −.104 | −1.181 | .239 |
Classification of the number of hospital beds | |||||
1 | −.120 | .074 | −.136 | −1.620 | .107 |
2 | −.196 | .067 | −.262 | −2.934 | .004 |
3 | .038 | .070 | .052 | .535 | .593 |