Table 1 Prevalence of malignant hyperthermia (MH) according to selected characteristics in the 47,178,322 delivery-related discharges of the 2003–2014 National Inpatient Sample

 Age (year)

   ≤ 19

18

0.41 (0.24–0.65)

0.96 (0.58–1.58)

1.02 (0.62–1.67)

  20–29

106

0.43 (0.36–0.52)

Reference

Reference

  30–39

86

0.51 (0.40–0.62)

1.17 (0.88–1.56)

1.15 (0.86–1.54)

   ≥ 40

--^b

--^b (0.12–0.89)

--^b (0.33–2.11)

0.85 (0.33–2.16)

 Race

  White, Non-Hispanic

102

0.50 (0.41–0.61)

Reference

Reference

  Black

24

0.46 (0.29–0.68)

0.90 (0.58–1.40)

0.82 (0.52–1.29)

  Hispanic

20

0.22 (0.14–0.34)

0.44 (0.27–0.71)

0.47 (0.29–0.76)

  Other

15

0.36 (0.20–0.59)

0.70 (0.40–1.20)

0.78 (0.45–1.35)

 Charlson comorbidity index

  0

215

0.46 (0.40–0.52)

–

–

   ≥ 1

0

0.00 (0.00–2.59)

–

–

 Comorbidity index for obstetric patients

  0 or 1

188

0.45 (0.39–0.52)

Reference

Reference

   ≥ 2

27

0.47 (0.31–0.69)

1.06 (0.71–1.58)

0.79 (0.52–1.19)

 Location and teaching status

  Rural

37

0.70 (0.49–0.97)

1.63 (1.12–2.39)

1.34 (0.91–1.98)

  Urban non-teaching

83

0.43 (0.34–0.54)

1.01 (0.75–1.36)

0.96 (0.71–1.30)

  Urban teaching

96

0.43 (0.35–0.52)

Reference

Reference

 Census region

  Northeast

20

0.26 (0.16–0.40)

Reference

Reference

  Midwest

51

0.51 (0.38–0.66)

1.96 (1.17–3.29)

1.71 (0.99–2.93)

  South

114

0.64 (0.53–0.77)

2.47 (1.54–3.98)

2.44 (1.50–3.96)

  West

29

0.25 (0.17–0.36)

0.98 (0.55–1.73)

1.11 (0.62–1.98)

Time period

 2003–2006

86

0.53 (0.43–0.66)

Reference

Reference

 2007–2010

69

0.43 (0.33–0.54)

0.81 (0.59–1.11)

0.81 (0.59–1.12)

 2011–2014

59

0.39 (0.30–0.51)

0.75 (0.54–1.04)

0.77 (0.55–1.09)