Effectiveness of measures to prevent needlestick injuries among ...

3 Descriptive epidemiology of NSI
by taking greater care during use and disposal of sharps, improved design of
sharp equipment, and placement of disposal units in closer proximity to work
areas.
Comparison of international rates of NSI is facilitated by the use of similarly formatted
reports, but methodological differences persist. For example, the data elements in-
cluded in each country’s reports were not identical, and the documentation accompa-
nying the reports was inadequate, e.g. failing to provide definitions or to specify
underlying assumptions. It is clear that different time frames were reported for various
countries participating in NSI surveillance and that the respective health systems are
not identical, but the data may lack comparability in other, less obvious ways. Factors
likely to differ internationally include the completeness and overall quality of the sur-
veillance systems. Within individual hospitals, there is likely to be underreporting of
NSI events, and the degree of underreporting could be differential by both occupation
and country. None of the surveillance data identified for this report included quality
audits. In addition, surveillance data describing NSI among HCW employed in non-
hospital settings (outpatient care, in-home care, emergency care, etc.) are currently
not tracked, so any national estimate of overall risk to HCW must be multiplied by an
unknown, but possibly large, factor.
As shown in the tables summarizing international data, surveillance systems typically
describe rates of NSI per 100 occupied hospital beds, as proportions of employees by
occupational category, and as proportions of events attributable to various types of
devices or procedures. These calculations might not provide the most accurate risk es-
timates. Because many hospitals employ contract workers, and part-time employment
or significant overtime (e. g. among medical interns) are also common, the use of
actual duty hours would account for work load and more accurately reflect time at risk.
Number of full-time equivalent employees (FTE) overall and in each occupational
category would offer a better approximation of risk compared to either occupied
hospital beds or total numbers of employees, and might result in a re-ordering of
the apparent risks among occupational groups. For example, data from Luhti et al.
showed a similar number of NSI among nurses and physicians overall (78 and 76 per
month, respectively). When the annualized rate of NSI by occupation was calculated,
Report „Needlestick injuries“ 28