Use of Proton Pump Inhibitors After Antireflux Surgery
Use of Proton Pump Inhibitors After Antireflux Surgery
Simple descriptive statistics with 95% CIs were used to present proportion redeeming index PPI prescription and taking up long-term PPI use.
We constructed Kaplan–Meier curves for the cumulative risk of redeeming an index prescription of PPI and for the cumulative risk of taking up long-term PPI use. Kaplan–Meier curves were created, stratified by the year of ARS in order to account for a general increase in the use of PPI. The year of index ARS was stratified into 1996–2000, 2001–2005 and 2006–2010.
We used Cox proportional hazards model with the independent variables gender, age at surgery (10-year intervals), year of index ARS (5-year intervals), use of PPI in the year before ARS (0, 1–89, 90–179, ≥180 DDDs) and use of non-steroidal anti-inflammatory drugs (NSAIDs) or antiplatelet drugs to estimate HRs for index prescription of PPI and long-term use of PPI. Use of NSAID and antiplatelet drugs were included as time-dependent variables. Antiplatelet drugs were separated into clopidogrel and acetylsalicylic acid.
In order to assess how much our outcome was affected by the use of PPI as a prophylactic agent during NSAID or antiplatelet therapy, we performed two different sensitivity analyses. In the first analysis, patients were censored at time of redemption of an NSAID or antiplatelet prescription. In the second analysis, we excluded PPI prescriptions, which we defined as being associated with NSAID or antiplatelet prescriptions. By our definition, PPI prescription redeemed less than 7 days before prescriptions of NSAID or antiplatelet drugs were excluded, as well as PPI prescriptions redeemed during ongoing NSAID or antiplatelet therapy. Ongoing NSAID or antiplatelet therapy was defined from the prescriptions' data by assuming a daily intake of 0.8 DDD from the date of redemption. The latter analysis, by its design, could only be applied to outcomes regarding index PPI prescriptions.
Statistics
Simple descriptive statistics with 95% CIs were used to present proportion redeeming index PPI prescription and taking up long-term PPI use.
We constructed Kaplan–Meier curves for the cumulative risk of redeeming an index prescription of PPI and for the cumulative risk of taking up long-term PPI use. Kaplan–Meier curves were created, stratified by the year of ARS in order to account for a general increase in the use of PPI. The year of index ARS was stratified into 1996–2000, 2001–2005 and 2006–2010.
We used Cox proportional hazards model with the independent variables gender, age at surgery (10-year intervals), year of index ARS (5-year intervals), use of PPI in the year before ARS (0, 1–89, 90–179, ≥180 DDDs) and use of non-steroidal anti-inflammatory drugs (NSAIDs) or antiplatelet drugs to estimate HRs for index prescription of PPI and long-term use of PPI. Use of NSAID and antiplatelet drugs were included as time-dependent variables. Antiplatelet drugs were separated into clopidogrel and acetylsalicylic acid.
In order to assess how much our outcome was affected by the use of PPI as a prophylactic agent during NSAID or antiplatelet therapy, we performed two different sensitivity analyses. In the first analysis, patients were censored at time of redemption of an NSAID or antiplatelet prescription. In the second analysis, we excluded PPI prescriptions, which we defined as being associated with NSAID or antiplatelet prescriptions. By our definition, PPI prescription redeemed less than 7 days before prescriptions of NSAID or antiplatelet drugs were excluded, as well as PPI prescriptions redeemed during ongoing NSAID or antiplatelet therapy. Ongoing NSAID or antiplatelet therapy was defined from the prescriptions' data by assuming a daily intake of 0.8 DDD from the date of redemption. The latter analysis, by its design, could only be applied to outcomes regarding index PPI prescriptions.