Outcomes from colonoscopy following referral from New Zealand general practice: a retrospective analysis.

BACKGROUND: New Zealand has high rates of colorectal cancer (CRC) but poor outcomes. Most patients with CRC are diagnosed following referral from general practice, where a general practitioner (GP) assesses symptoms according to national guidelines. All referred patients are then re-prioritised by the hospital system. The first objective of this study was to identify what proportion of patients referred by general practice to surgical/gastroenterology at Waikato District Health Board (DHB) had a colonoscopy. The second objective was to determine what proportion of these referrals have an underlying CRC and the factors associated with the likelihood of this diagnosis. METHODS: This study is a retrospective analysis of e-referral data for patients aged 30-70+ who were referred from 75 general practices to general surgery, gastroenterology or direct to colonoscopy at Waikato DHB, 01 January 2015-31 December 2017. Primary and secondary outcome measures included the proportion and characteristics of patients who were having colonoscopy, and of those, who were diagnosed with CRC. Data were analysed using chi square and logistic regression. RESULTS: 6718/20648 (32.5%) patients had a colonoscopy and 372 (5.5%) of these were diagnosed with CRC. The probability of having CRC following a colonoscopy increased with age (p value < 0.001). Females (p value < 0.001), non-Maori (p value < 0.001), and patients with a high suspicion of cancer (HSCan) label originating from their GP were more likely to have a colonoscopy, while the odds ratio of Maori having a colonoscopy was 0.66 (95% CI 0.60-0.73). The odds ratio of a CRC diagnosis following colonoscopy was 1.67 (95% CI 1.35-2.07) for men compared to women, and 2.34 (95% CI 1.70-3.22) for those with a GP HSCan label. Of the 585 patients referred with a GP HSCan, 423 (72.3%) were reprioritised by the hospital and 55 patients had their diagnosis unnecessarily delayed. CONCLUSIONS: If a GP refers a patient with an HSCan, and the patient receives a colonoscopy, then the likelihood of having CRC is almost 15.0%. This would suggest that these patients should be routinely prioritised without further triage by the hospital. Further research is needed to understand why Maori are less likely to receive a colonoscopy following referral from general practice.

Tobramycin Serum Concentrations After Aerosol and Oral Administration in Cystic Fibrosis.

We sought to describe tobramycin absorption after aerosol administration to cystic fibrosis (CF) subjects. Serum tobramycin concentrations were determined by modification of the radioimmuno-assay (RIA) technique, lowering the limit of detection from 1.0 &mgr;g ml(minus sign1) to 0.05 &mgr;g ml(minus sign1). In 37 studies, after aerosol delivery of 666 plus minus 195 mg to the airway of 24 patients, in which 222 samples were assayed, only 1 serum sample contained tobramycin at a concentration greater than 1.0 &mgr;g ml(minus sign1). Twenty-six of the 37 studies permitted estimation of pharmacokinetic parameters of tobramycin. The serum clearance of tobramycin following aerosol adminstration is 39.13 plus minus 0.393 L h(minus sign1) (mean plus minus standard error of the mean), with an elimination half-life of 3.072 plus minus 0.194 h. The half-life was significantly longer than that found after intravenous adminstration. The elimination rate constant (K(e)) was calculated to be 0.234 plus minus 0.002 h(minus sign1). Estimated total-body clearance in which systemic absorption was determined from sputum and urinary recovery of tobramycin was 0.094 plus minus 0.002 1 hr(minus sign1) kg(minus sign1). We also studied tobramycin absorption in six CF subjects after ingestion of a 80-mg m(minus sign2) dose, to gain insight into the tobramycin levels observed after swallowing an aerosol. Four out of the six subjects had measurable serum tobramycin concentration after ingestion. The serum concentration-time curve mirrored what was seen after aerosol administration. We concluded that tobramycin has poor systemic absorption in CF subjects after aerosol administration. Tobramycin in serum after aerosol administration is in part due to the gastrointestinal absorption of swallowed drug, as well as absorption from lower respiratory tract.