BackgroundThe National Reporting and Learning System (NRLS) collects reports about patient safety incidents in England. Government regulators use NRLS data to assess the safety of hospitals. This study aims to examine whether annual hospital incident reporting rates can be used as a surrogate indicator of individual hospital safety. Secondly assesses which hospital characteristics are correlated with high incident reporting rates and whether a high reporting hospital is safer than those lower reporting hospitals. Finally, it assesses which health-care professionals report more incidents of patient harm, which report more near miss incidents and what hospital factors encourage reporting. These findings may suggest methods for increasing the utility of reporting systems.MethodsThis study used a mix methods approach for assessing NRLS data. The data were investigated using Pareto analysis and regression models to establish which patients are most vulnerable to reported harm. Hospital factors were correlated with institutional reporting rates over one year to examine what factors influenced reporting. Staff survey findings regarding hospital safety culture were correlated with reported rates of incidents causing harm; no harm and death to understand what barriers influence error disclosure.Findings5,879,954 incident reports were collected from acute hospitals over the decade. 70.3% of incidents produced no harm to the patient and 0.9% were judged by the reporter to have caused severe harm or death. Obstetrics and Gynaecology reported the most no harm events [OR 1.61(95%CI: 1.12 to 2.27), p<0.01] and pharmacy was the hospital location where most near-misses were captured [OR 3.03(95%CI: 2.04 to 4.55), p<0.01]. Clinicians were significantly more likely to report death than other staff [OR 3.04(95%CI: 2.43 to 3.80) p<0.01]. A higher ratio of clinicians to beds correlated with reduced rate of harm reported [RR = -1.78(95%Cl: -3.33 to -0.23), p = 0.03]. Litigation claims per bed were significantly negatively associated with incident reports. Patient satisfaction and mortality outcomes were not significantly associated with reporting rates. Staff survey responses revealed that keeping reports confidential, keeping staff informed about incidents and giving feedback on safety initiatives increased reporting rates [r = 0.26 (p<0.01), r = 0.17 (p = 0.04), r = 0.23 (p = 0.01), r = 0.20 (p = 0.02)].ConclusionThe NRLS is the largest patient safety reporting system in the world. This study did not demonstrate many hospital characteristics to significantly influence overall reporting rate. There were no association between size of hospital, number of staff, mortality outcomes or patient satisfaction outcomes and incident reporting rate. The study did show that hospitals where staff reported more incidents had reduced litigation claims and when clinician staffing is increased fewer incidents reporting patient harm are reported, whilst near misses remain the same. Certain specialties report more near misses than others, and doctors r...

SummaryIn this paper we describe the use of a free duplication, sDp2 (I;f), for the recovery, maintenance, and analysis of mutations defining essential genes in the left third of Linkage Group I of Caenorhabditis elegans. The lethals were induced in a strain of genotype (sDp2) + /dpy-5 + unc-13/ dpy-5 unc-15 +, using either 12 mM ethylmethane sulphonate or 1500 r of gamma radiation. Lethal mutations linked to the dpy-5 unc-13 chromosome were recognized by the absence of Dpy-5 Unc-13 individuals amongst the self progeny and were maintained by isolating Unc-13 hermaphrodites. These strains – which have two mutant alleles of the essential gene and a wild-type allele on the duplication – are balanced, since crossing-over does not occur between sDp2 and the normal homologues. Using this sytem we have recovered 58 EMS-induced mutations. These have been characterized with regard to map position and complementation. Twenty-nine of the EMS-induced mutations lie to the left of dpy-5 and define 20 complementation groups; 3 were inseparable from dpy-5 and define 3 complementation groups; 21 were to the right and define 17 complementation groups. Among a set of 29 gamma radiation-induced lethal mutations, 17 appear to be single gene mutations or are very small deletions. We estimate that we have identified from one-sixth to one-half of the essential genes in the sDp2 region.

The central gene cluster of chromosome III was one of the ®rst regions to be sequenced by the Caenorhabditis elegans genome project. We have performed an essential gene analysis on the left part of this cluster, in the region around dpy-17III balanced by the duplication sDp3. We isolated 151 essential gene mutations and characterized them with regard to their arrest stages. To facilitate positioning of these mutations, we generated six new de®ciencies that, together with preexisting chromosomal rearrangements, subdivide the region into 14 zones. The 151 mutations were mapped into these zones. They de®ne 112 genes, of which 110 were previously unidenti®ed. Thirteen of the zones have been anchored to the physical sequence by polymerase chain reaction de®ciency mapping. Of the 112 essential genes mapped, 105 are within these 13 zones. They span 4.2 Mb of nucleotide sequence. From the nucleotide sequence data, 920 genes are predicted. From a Poisson distribution of our mutations, we predict that 234 of the genes will be essential genes. Thus, the 105 genes constitute 45% of the estimated number of essential genes in the physically de®ned zones and between 2 and 5% of all essential genes in C. elegans.

In the nematode Caenorhabditis elegans, recombination suppression in translocation heterozygotes is severe and extensive. We have examined the meiotic properties of two translocations involving chromosome I, szT1(I;X) and hT1(I;V). No recombination was observed in either of these translocation heterozygotes along the left (let-362-unc-13) 17 map units of chromosome I. Using half-translocations as free duplications, we mapped the breakpoints of szT1 and hT1. The boundaries of crossover suppression coincided with the physical breakpoints. We propose that DNA sequences at the right end of chromosome I facilitate pairing and recombination. We use the data from translocations of other chromosomes to map the location of pairing sites on four other chromosomes. hT1 and szT1 differed markedly in their effect on recombination adjacent to the crossover suppressed region. hT1 had no effect on recombination in the adjacent interval. In contrast, the 0.8 map unit interval immediately adjacent to the szT1(I;X) breakpoint on chromosome I increased to 2.5 map units in translocation heterozygotes. This increase occurs in a chromosomal interval which can be expanded by treatment with radiation. These results are consistent with the suggestion that the szT1(I) breakpoint is in a region of DNA in which meiotic recombination is suppressed relative to the genomic average. We propose that DNA sequences disrupted by the szT1 translocation are responsible for determining the frequency of meiotic recombination in the vicinity of the breakpoint.

The central gene cluster of chromosome III was one of the first regions to be sequenced by the Caenorhabditis elegans genome project. We have performed an essential gene analysis on the left part of this cluster, in the region around dpy-17III balanced by the duplication sDp3. We isolated 151 essential gene mutations and characterized them with regard to their arrest stages. To facilitate positioning of these mutations, we generated six new deficiencies that, together with preexisting chromosomal rearrangements, subdivide the region into 14 zones. The 151 mutations were mapped into these zones. They define 112 genes, of which 110 were previously unidentified. Thirteen of the zones have been anchored to the physical sequence by polymerase chain reaction deficiency mapping. Of the 112 essential genes mapped, 105 are within these 13 zones. They span 4.2 Mb of nucleotide sequence. From the nucleotide sequence data, 920 genes are predicted. From a Poisson distribution of our mutations, we predict that 234 of the genes will be essential genes. Thus, the 105 genes constitute 45% of the estimated number of essential genes in the physically defined zones and between 2 and 5% of all essential genes in C. elegans.