Limitations of our study include its observational nature. No causality is inferred in the observed relationship between abnormal systolic blood pressure and 30 day mortality or readmission. Although we have tried to adjust for a number of the most relevant variables, many unmeasured variables could be potential confounders. (we can add examples of variables here). The association of abnormal discharge vitals with adverse events has been demonstrated in the past. However, we formally quantify the magnitude of risks related specifically to abnormal systolic blood pressure ranges at discharge.
Other limitations of our study include the lack of inpatient and discharge antihypertensive medications data. Our patient population was a cohort of general medical/ surgical patients. Our findings may not be applicable for subgroups such as patients with heart failure, end stage liver disease, or post-acute stroke populations. Finally, we do not have information on readmissions outside our large hospital network, thus our rate of readmissions may be underestimated.