Extract
To The Editor:I read with great interest the article entitled "Thirty-Day Mortality
Following Hip Arthroplasty for Acute Fracture" (2004; 86:1983-8), by
Drs. Parvizi, Ereth, and Lewallen. I would be grateful for some more detail on
the calculation of thirty-day mortality.Thirty-day mortality should only be calculated when the status (i.e., dead
or alive) is known for each patient in the cohort or population thirty days
after the index event. Complete follow-up of the entire cohort is required for
this calculation. A thirty-day mortality of 2.4% is remarkably low for a
population of elderly patients with hip fractures, particularly as the
background mortality (death by natural causes) is 0.8% per month. Were the
authors calculating inhospital mortality, rather than true thirty-day
mortality? This is an important issue if mortality rates are to be compared
between institutions as the low mortality rate quoted by the authors could
have been due to a relatively short hospital stay with early rehabilitation in
the community. Reductions in length of stay also may explain the decrease in
mortality over the past three decades.