Discussion

From Wikipedia

Contents 1 Uniqueness and summary of main findings 2 Discussion of each of the main results 2.1 Authors agreeing with finding and discussion on mechanisms underlying the finding 2.2 Authors disagreeing with finding and reasons for disagreement 3 Study limitations 4 Knowledge implications and future research directions

Uniqueness and summary of main findings

State the uniqueness of your paper and summarize your main results. If possible, state how your manuscript is unique compared to the remaining literature, which usually starts with a sentence such as "To our knowledge, this is the first report to ..." Then summarize the three or four main findings of your paper so that they can serve as a summary of your results and prepare readers for a detailed discussion of each of your points.

• To our knowledge, this is the first analysis comparing length of hospital stay, postoperative in-hospital morbidity and mortality, and the rate of routine hospital discharge in patients undergoing LSR and OSR based on combined NIS databases. In our investigation patients undergoing LSR had a significantly shorter risk-adjusted mean length of hospital stay (LSR vs OSR, 7.47 vs 9.37 days; P<.001) and a higher rate of routine hospital discharge (OR, 2.21; 95% CI, 1.51-3.21; P<.001) compared with patients undergoing OSR. After adjusting for other covariates, patients undergoing LSR had statistically significantly fewer gastrointestinal tract complications (OR, 0.57; 95% CI, 0.35-0.93; P = .03) and overall complications (OR, 0.64; 95% CI, 0.47-0.88; P = .007). (Guller, 2003)

• These results indicate that lymphocytic infiltration of the tumour and a high CD4+:CD8+ T-cell ratio in particular are associated with a reduced risk of tumour recurrence following liver transplantation for HCC. Multivariate analysis demonstrated that a high CD4+:CD8+ T-cell ratio had a predictive value that was greater than either the Milan criteria or tumour grade and was equivalent to vasculkar invasion for predicting tumour recurrence. (Unitt,2006)

• In this study, we found no significant difference in the early complication rate nor in the local tumor progression rate between RF ablation of HCC nodules in high-risk locations and that of nodules elsewhere. Complete ablation was achieved in 229 of 231 nodules in high-risk locations and all of the 1,188 nodules found elsewhere. (Teratani,2006)

• In this study of acute low back pain, only 5 percent of the patients had not reported functional recovery at six months. However, 31 percent of the patients had not completely recovered at six months, which indicates that low-grade disability may last longer than previously thought. A study conducted at an HMO yielded similar results.18 Whether the patient saw a primary care physician, a chiropractor, or an orthopedic surgeon as the initial provider, the time to recovery from the acute back pain was essentially the same.Primary care physicians appear to offer efficient outpatient treatment, with some evidence that the most efficient care may be provided in a group-model HMO. Although charges per radiograph and per visit are lower for chiropractors than for medical doctors, the much higher number of treatments given by the chiropractors (requiring a larger number of visits) more than offsets this apparent advantage. For acute low back pain, the best care may be minimal care. (Carey, 1995).

• Bariatric surgery in morbidly obese individuals reverses, eliminates, or significantly ameliorates diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea. These benefits occur in the majority of patients who undergo surgery. With respect to type 2 diabetes, more than three quarters of the patients experienced complete resolution of their diabetes following bariatric surgery. Of those patients not experiencing complete resolution, more than half showed demonstrable improvement. Thus, about 85% of patients with diabetes experienced improvement in their diabetes course after bariatric surgery (Buchwald, 2004).

• A clear and consistent effect of statin-induced LDL-C lowering in significantly reducing the risk of coronary events, independent of sex or age, has been demonstrated in the individual studies and the meta-analysis presented here. A roughly 30% decline in coronary events is seen in all sex and age groups studied (LaRosa, 1999).

Discussion of each of the main results

Compare each main result mentioned in the first paragraph (text block) with the previous references from the literature. First discuss the findings that agree with previous studies, and point to the underlying mechanisms that might have lead to this agreement. For example, you might want to talk about pathophysiological mechanisms or social mechanisms that lead to all of the results converging to a common point. Then, approach the previous results in the literature that disagree with your results, attempting to provide explanations on why the disagreement occurred. Disagreements are usually related to a different research methodology and/or a different patient characteristics. Emphasize qualitative and quantitative of the results, if possible following Aquinas' advice: "When you meet a contradiction, make a distinction"

Authors agreeing with finding and discussion on mechanisms underlying the finding

• A Consensus Development Conference including 16 international experts for treatment and diagnosis of diverticular disease recently concluded that laparoscopic surgery is probably better than open surgery for length of hospital stay.3 Most matched-control20-23 and prospective cohort24 studies found LSR advantageous over OSR with respect to length of hospital stay. Other investigations comparing OSR and LSR procedures for different abdominal diseases confirmed this trend.25-27 One large US multicenter clinical trial reported a statistically significant but clinically modest (5.6 vs 6.4 days) advantage of laparoscopic surgery for patients with colorectal cancer.28 Another randomized controlled study from Germany reported a 1.5-day decrease in length of hospital stay after LSR (10.1 vs 11.6 days).29 (Guller, 2003)

• Our findings support the findings of previous volume outcome studies specific to total knee arthroplasty that demonstrated a statistically and clinically significant effect of surgeon volume on patient mortality5. Lavernia and Guzman5 used patient discharge data from Florida to assess the effects of surgical volume on short-term outcome, in terms of mortality, morbidity, length of stay, and hospital charges for primary and revision hip and knee arthroplasty. Patients of surgeons performing fewer than ten arthroplasties per year had higher mortality rates following primary or revision arthroplasty of the hip or knee. This association was also reported by Kreder et al.19, who used the Washington State Abstract Reporting System and found that a low volume of total hip arthroplasties performed by the provider was associated with higher rates mortality, postoperative infection, and severe surgical complications. In a secondary data analysis of the Medicare database, Katz et al.20 found that patients treated by surgeons who performed more than ten revision total hip arthroplasties per year had lower mortality rates; however, those authors found no significant association between surgeon volume and mortality after primary procedures.The heterogeneity of previous findings can be explained by skewed patient distributions among categorical volume groupings19,21 and samples that were not representative of the entire United States population19-21. In addition, possible differences in case mix and severity of illness among different patient populations may have led to different conclusions regarding the associations of surgeon volume with patient mortality and postoperative complications in these previous studies. As our investigation involved a nationally representative 20% probability sample of patients treated with knee arthroplasty, our findings can be generalized to the overall United States population and the target sample size exceeds that of previous studies. Moreover, in the present investigation, there were similar percentages of patients in each volume grouping of primary total knee arthroplasties and case-mix differences were considered. These considerations increase our confidence in the validity of our findings.(Hervey, 2006)

• Our finding that the higher charges by chiropractors reflected a larger number of visits per episode of back pain is similar to the result of a secondary analysis of data from the Rand Health Insurance Experiment, performed by Shekelle et al.19 They reported a mean of 10.4 visits to chiropractors per episode, as compared with 2.3 visits to primary care physicians.Our finding that the patients in the chiropractic strata were more satisfied with their care than the patients in the other strata is consistent with the results of a previous study by Cherkin and MacCornack.11 Multiple outcome measures (the time to functional recovery and return to work, the time to complete recovery, and functional status) were similar in the chiropractic and physician strata, yet the patients seen by chiropractors reported greater satisfaction with the examination and explanation of the problem. Patients and insurers need to address the trade-off between the substantially lower charges by primary care practitioners and the higher level of satisfaction with the care that chiropractors and orthopedic surgeons provide.(Carey, 1995)

• With respect to type 2 diabetes, more than three quarters of the patients experienced complete resolution of their diabetes following bariatric surgery. Of those patients not experiencing complete resolution, more than half showed demonstrable improvement. Thus, about 85% of patients with diabetes experienced improvement in their diabetes course after bariatric surgery. (Buchwald, 2004).

• It is clear that there is no effect of these interventions on noncardiovascular mortality. Neither those studies whose participants had initially high cholesterol levels (4S, LIPID, and WOSCOPS) nor those whose initial cholesterol levels were lower (CARE and AFCAPS/TexCAPS) reported any increase in noncardiovascular mortality. Because these studies were limited for approximately 5 years, they cannot offer information other than the possible effects of longer exposure to statins or cholesterol lowering. Some of the guidelines and policies that resulted from an unwillingness to extrapolate earlier reported data to women and the elderly should be revisited. Policies designed to limit screening in women and elderly persons10 make no sense and, in fact, are potentially harmful because they diminish in the eyes of both the public and the practicing physician the importance of cholesterol interventions in these groups (LaRosa, 1999).

Authors disagreeing with finding and reasons for disagreement

• The variability of the published results regarding the length of hospital stay is considerable and may be due to a variety of factors. The current literature describes that the difference may be affected by hospital factors30-31 or social habits32 rather than reflecting differences caused by the operative technique itself. Moreover, further discrepancies may arise from diverse health care policies in different countries or different regions within a country. For instance, while Kohler et al21 from Germany reported a length of hospital stay of 7.9 days for patients undergoing LSR and 14.3 days for patients undergoing OSR, Senagore et al24 in Ohio found the the length of hospital stay was 3.1 days for patients undergoing LSR vs 6.8 days for patients undergoing OSR, and Faynsod et al20 in California found that the length of hospital stay was 4.8 days for patients undergoing LSR and 7.8 days for patients undergoing OSR. The shorter length of stay in patients undergoing laparoscopic surgery can be explained by decreased postoperative pain,20, 26, 33 less fatigue,29 and faster recovery of intestinal peristalsis.20-21,33 (Guller, 2003).

• The treatment success rate, higher than those reported by others,16,34,35 was probably the result of our accumulated experience in percutaneous ablation procedures with ethanol,microwave, and RF, amounting to a total of 4,000 cases.33 We have perfected techniques for inserting an electrode into tumors almost anywhere in the liver without puncturing large vessels or bile ducts by, for example, changing the patient position and selecting the insertion site. In addition, we place no restrictions on the number of treatment sessions. We have repeated RF ablation until necrosis of the entire tumor was confirmed on CT. Although this may have increased the number of treatment sessions, complete ablation is possibly associated with improved prognosis vTeratani,2006).

• While there was no difference in early complication rates according to tumor location, the overall early complication rate of 4.2% in this study may be slightly higher than those reported in other studies.21,37 The effort of thorough ablation increased the total number of electrode insertions, and this may have led to an increase in complications"(Teratani,2006).

• Several studies have reported improved outcomes among patients undergoing spinal manipulation, as compared with those receiving medical treatments.20,21,22,23,24 Our study did not confirm these results. Several explanations are possible. There may have been a benefit from spinal manipulation, but uncontrolled confounding due to unmeasured differences in the case mix may have obscured this effect. The differences among the strata in our study were actually smaller after adjustment for the presence of sciatica, the duration of pain, and functional status, indicating that significant differences in recovery rates among the strata would have been unlikely after a further adjustment for case mix. Alternatively, the treatment provided by the randomly selected chiropractors in our study may not have been as effective as the treatment provided in trials in which the intervention was standardized (Carey, 1995).

Study limitations

Point to the main limitations of your study and what you have done to minimize those limitations (if nothing can be done to minimize them, explain how the limitation didn't have much of an influence on the results). Also mention analyses that were not performed in the present study and that should be approached in subsequent studies in order to complement the results.

• We would like to acknowledge the limitations of our study. First and most importantly, this is a large observational study and not a randomized clinical trial, and thus, patients undergoing LSR differed with respect to sociodemographics and comorbidities from patients undergoing OSR. However, even after risk-adjusting for patient and hospital level characteristics in multivariable analyses, LSR remained clearly advantageous over OSR for most outcomes under investigation. Second, as our investigation is based on combined large administrative databases, it is possible that some procedures, diagnoses, and end points are miscoded. It can be assumed, however, that length of hospital stay, hospital discharge status, and vital status were adequately reported as these end points are not subject to subjective evaluation. Comparative analyses of the NIS databases with other databases concluded that the NIS databases perform very well and that NIS estimates such as in-hospital mortality and length of hospital stay are accurate and precise for both large groups ranging from the population of the United States, and small subsets with specific conditions.45-46 Moreover, miscoding is likely to occur similarly in both LSR and OSR subsets. The problem of miscoding can be assumed to be less pertinent while comparing the 2 groups (Guller, 2003).

• The influence of bile duct injury on long-term prognosis remains to be studied. Tumor seeding is another major late complication of RF ablation. Although we did not analyze this in the present study, it is not likely to be related to the adjacency to large vessels or extrahepatic organs (Teratani,2006).

• Our study was observational; patients were not randomly assigned to the various types of providers. A randomized trial would be very difficult to perform in a community setting. Since the patients in our study were enrolled at the time of the initial office visit, we could not assess their functional status before the episode of back pain. The outcomes of care provided by practitioners who rarely serve as first-contact providers (e.g., physical therapists and rheumatologists) could not be assessed. In addition, our analysis of charges relies on estimates, but the differences among the strata of providers were substantial. Do our findings simply reflect the natural history of acute low back pain, with essentially no modification by medical or chiropractic care? Since our study did not include a group of patients who sought no care for their acute back pain, we cannot answer this question. Improved techniques of self-care should be investigated. Acute back pain is sufficiently disabling, however, that many persons will continue to seek professional care(Carey, 1995).

• The heterogeneity of the immediate postoperative and long-term morbidity data did not allow for meta-analysis. However, although these data are diverse, operation-specific reports of adverse outcomes are available for gastric banding,59-61 gastric bypass,28, 30, 62 gastroplasty,23, 63-64 and biliopancreatic diversion or duodenal switch (Buchwald, 2004).

• Finally, currently available data do not allow us to draw any conclusions about the effects on total mortality in these sex and age groups beyond those that are already published. It would, however, be wrong to conclude that an effect on morbidity has no implications for the potential effects on mortality. The prevention of a morbid event also prevents that individual from graduating into a much higher risk category for subsequent mortality (LaRosa, 1999).

Knowledge implications and future research directions

State what knowledge implication result from your results. In other words, state how practice should be different from now on based on your results. Then state what should be the next steps taken in terms of research. Of importance, your suggestions for the next steps in terms of research might be a project you are already working on or a research proposal that you would like to see funded.

• We have shown that LSR has significant advantages over OSR with respect to length of hospital stay, rate of routine hospital discharge, and postoperative in-hospital morbidity. The advantage of LSR remains clinically and statistically significant in elderly and nonelectively admitted patients for length of hospital stay and routine hospital discharge. To our knowledge, this is the first investigation comparing end points after LSR and OSR based on a representative US nationwide database. Our findings may have important health care implications, not only resulting in clinical patient benefit but also in lowering hospital costs. Exponentially increasing health care costs have stimulated a massive health care reform effort seeking cost containment. It is imperative that health care professionals make fiscally prudent decisions, as the present environment necessitates a critical appraisal of apparently equi-efficacious therapeutic modalities. However, all aspects of LSR and OSR must be compared, including postoperative pain, patient's quality of life, missed days of work, procedural costs, total costs, and long-term complications. The present investigation based on representative US nationwide patient samples is only the first step in assessing all of these aspects. Further analyses to evaluate the aforementioned end points are required to define whether LSR should be considered the treatment of choice in patients with diverticular disease (Guller, 2003).

• In conclusion, it can be stated with confidence that RF ablation can be performed effectively on nodules adjacent to large vessels or extrahepatic organs, with the proviso that the operators possess sufficient experience and skill (Teratani,2006).

• Further research is needed to examine the consistency of these associations over time and to evaluate etiological factors resulting in these associations. The degree to which the experience of the surgeon or care team, compared with patient selection, in-hospital patient management and rehabilitation, and post-discharge care, underlies these differences in patient outcomes will drastically affect the policy changes that are necessary to improve the quality of care. Prospective studies are required. Effective changes in policy will also need to take into account evidence supporting the cost-effectiveness of regionalization of total knee arthroplasties and incorporate patient preference for convenient access to care. Finally, it is important to consider the relationship between provider volume and patient-based measures of outcome, such as postoperative pain, mobility, days missed from work, quality of life, and intensity of resource utilization. Although provider volume is a crude measure of quality of care, our investigation validates the hypothesis that volume standards could decrease mortality following total knee arthroplasties (Hervey,2006).

• Our study has implications for health care policy. The costs of acute back pain are substantial. Previous studies by our group have shown that 3 percent of the North Carolina population seek care for acute low back pain each year.8 It is important to compare the effectiveness of short and long courses of spinal manipulation. Since the choice between specialists and doctors of chiropractic as primary providers of care is not associated with a difference in the functional outcome, the marginal costs (i.e., for increased care without an improvement in function) are very high. Although medical researchers should continue to seek more effective therapies for acute back pain, the continued use of marginally effective therapies and expensive, low-yield diagnostic tests has led to a level of health care utilization that probably cannot be sustained in an era of increasingly limited resources (Carey, 1995).

• In summary, in addition to the effective weight loss achieved by patients undergoing bariatric surgical procedures, a substantial majority of patients with diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea experienced complete resolution or improvement of their comorbid condition (Buchwald, 2004).

• In summary, the benefits of LDL-C lowering induced by statins appear to be universal, not defined by sex or age. It is important now to work to extend these benefits to all who are at risk for atherosclerotic cardiovascular disease (LaRosa, 1999).