An analysis of the Oxford hip and knee scores and their relationship to early joint revision in the New Zealand Joint Registry.

We analysed data from the Oxford hip and knee questionnaires collected by the New Zealand Joint Registry at six months and five years after joint replacement, to determine if there was any relationship between the scores and the risk of early revision. Logistic regression of the six-month scores indicated that for every one-unit decrease in the Oxford score, the risk of revision within two years increased by 9.7% for total hip replacement (THR), 9.9% for total knee replacement (TKR) and 12.0% for unicompartmental knee replacement (UKR). Our findings showed that 70% of the revisions within two years for TKR and 67% for THR and UKR would have been captured by monitoring the lowest 22%, 28% and 28%, respectively, of the Oxford scores. When analysed using the Kalairajah classification a score of < 27 (poor) was associated with a risk of revision within two years of 7.6% for THR, 7.0% for TKR and 24.3% for UKR, compared with risks of 0.7%, 0.7% and 1.8%, respectively, for scores > 34 (good or excellent). Our study confirms that the Oxford hip and knee scores at six months are useful predictors of early revision after THR and TKR and we recommend their use for the monitoring of the outcome and potential failure in these patients.

Clinical assessment of a new anaesthetic drug administration system: a prospective, controlled, longitudinal incident monitoring study.

A safety-orientated system of delivering parenteral anaesthetic drugs was assessed in a prospective incident monitoring study at two hospitals. Anaesthetists completed an incident form for every anaesthetic, indicating if an incident occurred. Case mix data were collected and the number of drug administrations made during procedures estimated. From February 1998 at Hospital A and from June 1999 at Hospital B, until November 2003, 74,478 anaesthetics were included, for which 59,273 incident forms were returned (a 79.6% response rate). Fewer parenteral drug errors occurred with the new system than with conventional methods (58 errors in an estimated 183,852 drug administrations (0.032%, 95% CI 0.024-0.041%) vs 268 in 550,105 (0.049%, 95% CI 0.043-0.055%) respectively, p = 0.002), a relative reduction of 35% (difference 0.017%, 95% CI 0.006-0.028%). No major adverse outcomes from these errors were reported with the new system while 11 (0.002%) were reported with conventional methods (p = 0.055). We conclude that targeted system re-design can reduce medical error.

Cerebrovascular disease as a general medicine discharge diagnosis: assessment of diagnostic agreement on case note review.

BACKGROUND: Accurate clerical coding of discharge diagnoses is important partly because results may be used to derive a recommended costing for hospital length of stays (LOS). Some authors think that discharge coding undertaken by clinicians will result in less diagnostic misclassification than clerical coding. This presupposes a high degree of between-observer diagnostic agreement between clinicians. AIMS: To compare discharge coding undertaken by two general physicians, for patients receiving a clerical discharge code of cerebrovascular disease. The recommended LOS was then calculated from each observer's discharge codes using the Physicians Diagnosis Related Group Working Guidebook. RESULTS: Eighty-two cases were coded as stroke by the clerical coder. Both medical coders agreed with this diagnosis in 68 (83%) of these cases. The corresponding figure for cases coded by the clerical coder as transient cerebral ischaemia was 47% (32/68) agreement between all three observers. Correcting for chance agreement between medical observers using the kappa statistic, a value of 0.64 was obtained for the combined stroke and transient cerebral ischaemia discharges, suggesting moderate diagnostic agreement. Using the clerical coder's results, the mean recommended LOS for all cases of cerebrovascular disease over the study period was calculated at 6.68 days. The corresponding values for the two medical coders were 6.68 days and 6.75 days. CONCLUSIONS: Diagnostic agreement between clinicians was moderate. Consideration of alternative diagnostic possibilities and the difficulty in determining the duration of neurological deficit were the main reasons for diagnostic disagreement. The mean recommended LOS was similar, however, when comparing results from all three observers.

Comparison of methods of assessment of renal function in patients with cancer treated with cisplatin, carboplatin or methotrexate.

In patients with cancer treated with cisplatin, carboplatin or methotrexate creatinine clearance calculated using the Cockcroft-Gault formula was compared with measured clearance and with the glomerular filtration rate. In 106 patients the average squared difference for calculated and 24 hour urine creatinine clearance was 0.288, n = 606; and for calculated creatinine clearance and glomerular filtration rate (measured using diethylenetriaminepenta-acetic acid, DTPA), 0.212, n = 34. On 35 of 606 occasions (6%) in 18 patients (17%), the calculated clearance overestimated the 24-hour urine creatinine clearance when it was less than 1 mL/s. In all but one patient, this was explained by factors leading to renal impairment (seven patients) or overestimation of clearance (ascites in two patients) or by an isolated low value of 24-hour urine creatinine clearance (eight patients). Declining renal function with increasing total dose of cisplatin was detected by both calculated and 24-hour urine creatinine clearance in patients with germ cell tumours. Derivation of an equation to predict creatinine clearance showed a linear association with plasma creatinine concentration, patient age, weight and gender. Variability in cancer patients was similar to that in the original Cockcroft-Gault study. Calculation of creatinine clearance can be used in cancer patients to monitor treatment with renally-eliminated chemotherapy agents.