J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Original Article

Volume 10, Number 6, June 2018, pages 499-507

Improved Outcomes Associated With the Use of Intravenous Acetaminophen for Management of Acute Post-Surgical Pain in Cesarean Sections and Hysterectomies

Figure 1. Patient selection in OB/GYN patients treated with oral vs. IV APAP. The study identified 30,198 unique Cesarean section and hysterectomy patients who were treated with oral APAP and 8,693 Cesarean section and hysterectomy patients who were treated with IV APAP. IV: intravenous; APAP: acetaminophen; OB/GYN: obstetrics and gynecology.

**Table 1.** Demographics and Baseline Characteristics for Cesarean Section Surgery Patients
Variable	IV APAP (N = 4,512)	%	Oral APAP (N= 24,612)	%
A total of 29,124 Cesarean section surgery patients were analyzed. IV: intravenous; APAP: acetaminophen; SD: standard deviation; BMI: body mass index.
Age (mean, SD)	30.9 (6.0)		29.6 (5.9)
Imputed BMI (mean, SD)	33.3 (6.8)		33.8 (7.0)
Race
Caucasian	2,181	48.3%	17,180	69.8%
African American	1,656	36.7%	3,127	12.7%
Asian/other	465	10.3%	3,006	12.2%
Hispanic	54	1.2%	960	3.9%
Missing/unknown	156	3.5%	339	1.4%
Admission source
Emergency	1,717	38.1%	109	0.4%
Healthcare facility	844	18.7%	137	0.6%
Non-healthcare facility	1,559	34.6%	20,245	82.3%
Other	56	1.2%	2,170	8.8%
Unknown	336	7.5%	1,951	7.9%
Admission type
Emergency	1,785	39.6%	415	1.79%
Urgent	520	11.5%	3,806	15.5%
Elective	1,980	43.9%	18,430	74.9%
Other	4	0.1%	677	2.8%
Unknown	223	4.9%	1,284	5.2%
Hospital characteristics
Urban	1,497	33.2%	18,716	76.0%
Teaching hospital (missing 111 patients)	3,793	84.2%	14,651	59.8%
Bed size
< 200	345	7.7%	7,282	29.6%
200 to 299	618	13.7%	2,991	12.2%
300 to 499	831	18.4%	7,540	30.6%
500+	2,718	60.2%	6,799	27.6%
Census region
Midwest	490	10.9%	6,977	28.4%
Northeast	2,852	63.2%	8,448	34.3%
South	739	16.4%	5,970	24.3%
West	431	9.6%	3,217	13.1%

Table 1. Demographics and Baseline Characteristics for Cesarean Section Surgery Patients

Variable

IV APAP (N = 4,512)

Oral APAP (N= 24,612)

A total of 29,124 Cesarean section surgery patients were analyzed. IV: intravenous; APAP: acetaminophen; SD: standard deviation; BMI: body mass index.

Age (mean, SD)

30.9 (6.0)

29.6 (5.9)

Imputed BMI (mean, SD)

33.3 (6.8)

33.8 (7.0)

Race

Caucasian

2,181

48.3%

17,180

69.8%

African American

1,656

36.7%

3,127

12.7%

Asian/other

465

10.3%

3,006

12.2%

Hispanic

1.2%

960

3.9%

Missing/unknown

156

3.5%

339

1.4%

Admission source

Emergency

1,717

38.1%

109

0.4%

Healthcare facility

844

18.7%

137

0.6%

Non-healthcare facility

1,559

34.6%

20,245

82.3%

Other

1.2%

2,170

8.8%

Unknown

336

7.5%

1,951

7.9%

Admission type

Emergency

1,785

39.6%

415

1.79%

Urgent

520

11.5%

3,806

15.5%

Elective

1,980

43.9%

18,430

74.9%

Other

0.1%

677

2.8%

Unknown

223

4.9%

1,284

5.2%

Hospital characteristics

Urban

1,497

33.2%

18,716

76.0%

Teaching hospital (missing 111 patients)

3,793

84.2%

14,651

59.8%

Bed size

< 200

345

7.7%

7,282

29.6%

200 to 299

618

13.7%

2,991

12.2%

300 to 499

831

18.4%

7,540

30.6%

500+

2,718

60.2%

6,799

27.6%

Census region

Midwest

490

10.9%

6,977

28.4%

Northeast

2,852

63.2%

8,448

34.3%

South

739

16.4%

5,970

24.3%

West

431

9.6%

3,217

13.1%

**Table 2.** Demographics and Baseline Characteristics for Hysterectomy Surgery Patients
Variable	IV APAP (N = 4,181)	%	Oral APAP (N = 5,586)	%
A total of 9,767 hysterectomy surgery patients were analyzed. IV: intravenous; APAP: acetaminophen; SD: standard deviation; BMI: body mass index.
Age (mean, SD)	47.4 (12.0)		47.1 (11.5)
Imputed BMI (mean, SD)	30.9 (7.7)		30.8 (7.4)
Race
Caucasian	2,833	67.8%	4,013	71.8%
African American	1,009	24.1%	1,069	19.1%
Asian/other	265	6.3%	369	6.6%
Hispanic	18	0.4%	79	1.4%
Missing/unknown	56	1.3%	56	1.0%
Admission source
Emergency	31	0.7%	11	0.2%
Healthcare facility	10	0.2%	10	0.2%
Non-healthcare facility	3,448	82.5%	4,939	88.4%
Other	141	3.4%	95	1.7%
Unknown	246	5.9%	531	9.5%
Admission type
Emergency	165	4.0%	136	2.4%
Urgent	56	1.3%	149	2.7%
Elective	3,833	91.7%	5,213	93.3%
Other	85	2.0%	2	0.1%
Unknown	42	1.0%	86	1.5%
Hospital characteristics
Urban	2,690	64.3%	5,056	90.5%
Teaching hospital (22 patients missing)	2,962	71.2%	3,317	59.4%
Bed size
< 200	848	20.3%	1,389	24.9%
200 to 299	763	18.3%	1,120	20.1%
300 to 499	1,533	36.7%	1,539	27.6%
500+	1,037	24.8%	1,538	27.5%
Census region
Midwest	957	22.9%	1,298	23.2%
Northeast	1,046	25.0%	2,047	36.7%
South	1,507	36.0%	1,668	29.9%
West	671	16.1%	573	10.3%

Table 2. Demographics and Baseline Characteristics for Hysterectomy Surgery Patients

Variable

IV APAP (N = 4,181)

Oral APAP (N = 5,586)

A total of 9,767 hysterectomy surgery patients were analyzed. IV: intravenous; APAP: acetaminophen; SD: standard deviation; BMI: body mass index.

Age (mean, SD)

47.4 (12.0)

47.1 (11.5)

Imputed BMI (mean, SD)

30.9 (7.7)

30.8 (7.4)

Race

Caucasian

2,833

67.8%

4,013

71.8%

African American

1,009

24.1%

1,069

19.1%

Asian/other

265

6.3%

369

6.6%

Hispanic

0.4%

1.4%

Missing/unknown

1.3%

1.0%

Admission source

Emergency

0.7%

0.2%

Healthcare facility

0.2%

Non-healthcare facility

3,448

82.5%

4,939

88.4%

Other

141

3.4%

1.7%

Unknown

246

5.9%

531

9.5%

Admission type

Emergency

165

4.0%

136

2.4%

Urgent

1.3%

149

2.7%

Elective

3,833

91.7%

5,213

93.3%

Other

2.0%

0.1%

Unknown

1.0%

1.5%

Hospital characteristics

Urban

2,690

64.3%

5,056

90.5%

Teaching hospital (22 patients missing)

2,962

71.2%

3,317

59.4%

Bed size

< 200

848

20.3%

1,389

24.9%

200 to 299

763

18.3%

1,120

20.1%

300 to 499

1,533

36.7%

1,539

27.6%

500+

1,037

24.8%

1,538

27.5%

Census region

Midwest

957

22.9%

1,298

23.2%

Northeast

1,046

25.0%

2,047

36.7%

South

1,507

36.0%

1,668

29.9%

West

671

16.1%

573

10.3%

**Table 3.** Multivariable Results for Cesarean Sections and Hysterectomies
Outcome	IPW-RA modeling results	GLM results
Results are provided as value (95% CI). RR: relative risk; N/D: not determined due to lack of convergence; GLM: generalized linear model; IPW-RA: inverse-probability-weighted regression adjustment. Sample sizes in the IPW-RA method are smaller than the GLM/logistic regression models by a small amount because patients with extreme propensities are dropped from the analysis as per convention; the IPW-RA method was unable to derive an estimate for Total pharmacy costs in Cesarean sections
Cesarean sections
Length of stay	28,910	-0.45 days (-0.72, -0.17)	< 0.001	28,998	-0.51 days (-0.82, -0.19)	0.003
Total morphine consumption (MME) per day; Day 0 to Day 3	28,904	-1.6 mg (-2.5, -0.8)	< 0.001	28,992	-0.1 mg (-1.7, 1.5)	0.909
Total pharmacy costs (Winsorized at 2.5%) (USD)	N/D	N/D	N/D	27,552	-13 (-643, 617)	0.969
Opioid related adverse events (ORADEs)	28,910	RR = 0.45 (0.26, 0.78)	< 0.001	28,998	RR = 0.38 (0.16, 0.90)	0.027
Hysterectomies
Length of stay	9,697	-0.27 days (-0.46, -0.08)	0.005	9,711	-0.28 days (-0.53, -0.04)	0.003
Total morphine consumption (MME) per day; Day 0 to Day 3	9,686	-1.7 mg (-3.1, -0.3)	0.014	9,700	-1.0 mg (-3.9, 1.9)	0.511
Total pharmacy costs (Winsorized at 2.5%) (USD)	9,204	-107 (-382, 167)	0.444	9,218	-189 (-828, 449)	0.562
Opioid related adverse events (ORADEs)	9,697	RR = 1.09 (0.77, 1.41)	0.565	9,711	RR = 1.39 (0.95, 2.05)	0.090

Table 3. Multivariable Results for Cesarean Sections and Hysterectomies

Outcome

IPW-RA modeling results

GLM results

Sample size

Effect estimate/difference with 95% CI from the IPW-RA method

P value

GLM model summary

P value

Results are provided as value (95% CI). RR: relative risk; N/D: not determined due to lack of convergence; GLM: generalized linear model; IPW-RA: inverse-probability-weighted regression adjustment. Sample sizes in the IPW-RA method are smaller than the GLM/logistic regression models by a small amount because patients with extreme propensities are dropped from the analysis as per convention; the IPW-RA method was unable to derive an estimate for Total pharmacy costs in Cesarean sections

Cesarean sections

Length of stay

28,910

-0.45 days (-0.72, -0.17)

< 0.001

28,998

-0.51 days (-0.82, -0.19)

0.003

Total morphine consumption (MME) per day; Day 0 to Day 3

28,904

-1.6 mg (-2.5, -0.8)

< 0.001

28,992

-0.1 mg (-1.7, 1.5)

0.909

Total pharmacy costs (Winsorized at 2.5%) (USD)

N/D

27,552

-13 (-643, 617)

0.969

Opioid related adverse events (ORADEs)

28,910

RR = 0.45 (0.26, 0.78)

< 0.001

28,998

RR = 0.38 (0.16, 0.90)

0.027

Hysterectomies

Length of stay

9,697

-0.27 days (-0.46, -0.08)

0.005

9,711

-0.28 days (-0.53, -0.04)

0.003

Total morphine consumption (MME) per day; Day 0 to Day 3

9,686

-1.7 mg (-3.1, -0.3)

0.014

9,700

-1.0 mg (-3.9, 1.9)

0.511

Total pharmacy costs (Winsorized at 2.5%) (USD)

9,204

-107 (-382, 167)

0.444

9,218

-189 (-828, 449)

0.562

Opioid related adverse events (ORADEs)

9,697

RR = 1.09 (0.77, 1.41)

0.565

9,711

RR = 1.39 (0.95, 2.05)

0.090