title: Histamine H2-Blocker and Proton Pump Inhibitor Use and the Risk of Pneumonia in Acute Stroke: A Retrospective Analysis on Susceptible Patients.
abstract: BACKGROUND
  Although histamine H2-blockers (H2B) and proton pump inhibitors (PPI) are used commonly to prevent gastrointestinal bleeding in acute stroke, they are implicated in the increased risk of pneumonia in other disease populations. In acute stroke, the presence of distinctive risk factors of pneumonia, including dysphagia and impaired consciousness, makes inclusive analysis vulnerable to confounding. Our aim was to assess whether acid-suppressive drugs increase pneumonia in acute stroke in a population controlled for confounding.
  
  
  METHODS
  We analyzed acute stroke patients admitted to a tertiary care hospital. To minimize confounding, we only included subjects who could not feed orally during 14 days of hospitalization. Exposure was defined as H2B or PPI, given in days; the outcome was development of pneumonia within this period. The incidence was calculated from the total number of pneumonias divided by the sum of person-days at risk. We additionally performed multivariate Poisson regression and propensity score analyses, although the restriction largely eliminated the need for multivariate adjustment.
  
  
  RESULTS
  A total of 132 pneumonias occurred in 3582 person-days. The incidence was 3.69%/person-day (95% confidence interval (CI); 3.03-4.37%/day). All subjects had dysphagia. Stroke severity and consciousness disturbances were well-balanced between the groups exposed to H2B, PPI, or none. The relative risk (RR) compared with the unexposed was 1.22 in H2B (95%CI; 0.83-1.81) and 2.07 in PPI (95% CI; 1.13-3.62). The RR of PPI compared with H2B was 1.69 (95%CI; 0.95-2.89). In multivariate regression analysis, the RRs of H2B and PPI were 1.24 (95% CI; 0.85-1.81) and 2.00 (95% CI; 1.12-3.57), respectively; in propensity score analyses they were 1.17 (95% CI; 0.89-1.54) and 2.13 (95% CI; 1.60-2.84).
  
  
  CONCLUSIONS
  The results of this study suggested that prophylactic acid-suppressive therapy with PPI may have to be avoided in acute stroke patients susceptible to pneumonia.
authors.affiliation: Department of Neurological Surgery, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Arai
authors.affiliation: Department of Neurology, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Nakamizo
authors.affiliation: Department of Neurology, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Ihara
authors.affiliation: Department of Neurology, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Koide
authors.affiliation: Department of Neurological Surgery, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Department of Neurological Surgery, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Tabuse
authors.affiliation: Department of Neurological Surgery, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Miyazaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006632:Histamine / Q000737:chemistry*; D006635:Histamine H2 Antagonists / Q000009:adverse effects*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D011014:Pneumonia / Q000139:chemically induced / Q000453:epidemiology*; D057216:Propensity Score; D054328:Proton Pump Inhibitors / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000150:complications / Q000188:drug therapy*
chemical_list: D006635:Histamine H2 Antagonists; D054328:Proton Pump Inhibitors; D006632:Histamine