Peer Writing 3 - Simpson's Kidney Stones.docx

PW3: Analyzing a Scientific Study Files should be in PDF format, submitted in D2L. Instructions To successfully complete the peer essay assignment below: ● Read through the prompt below, which includes data on the outcomes of patients suffering from kidney stones who underwent one of two procedures. ● Your task is to write a brief report based on these data to help surgeons understand if and when to apply one treatment over the other, using statistics mentioned in class (e.g., different in conditional proportions, relative risk) to justify your position. ● Your critique should be concise, no more than 1.5 pages, single-spaced, 12-point font. The data: Evaluating medical procedures ~ The following data refer to a study comparing treatments for kidney stones. Kidney stones are hard deposits of minerals and salts that accumulate over time as kidneys clean blood circulating throughout the body. As they increase in size, they can cause extreme pain, infection, and pose a serious health risk to the individual. In many cases, kidney stones can pass through the urinary system without medical assistance (although this does cause substantial pain!). Individuals diagnosed with larger kidney stones typically undergo an operation to remove them. Two of the treatments studied were Treatment A = open surgery, an invasive procedure involving large incisions through the abdomen that requires substantial patient recovery time and Treatment B = percutaneous nephrolithotomy , a less invasive procedure where a small scope is inserted through an incision in your back to remove the kidney stones. Treatments are deemed 'successful' if, after three months, the kidney stones were either eliminated or reduced in size to less than 2 mm (at which point they can pass through the urinary system). The goal of this study was to answer the following question: When should doctors recommend open surgery and when should doctors recommend nephrolithotomy to patients suffering from kidney stones? There are several possible positions you could take in response to this question. For instance, you could argue: A. Doctors should always favor open surgery. B. Doctors should always favor nephrolithotomy. C. Doctors should sometimes favor open survey and other times favor nephrolithotomy. D. Doctors should not favor either surgery option, as they are equally likely to produce successful outcomes.

The tables below show the global results of the two treatment types along with the results of each treatment when the size of the kidney stones removed are taken into consideration. A kidney stone is considered large if it is initially more than 5 mm in diameter when detected and small if it is between 2 and 5 mm. Overall results Small stones (under 5mm) Large stones (5 mm or greater) Treatment Succes s Failur e Tot al Succes s Failur e Tot al Ris k RR Succes s Failur e Tot al Risk Open surgery 273 77 350 81 6 87 .931 192 71 263 0.7300 Nephrolithoto my 289 61 350 234 36 270 .867 55 25 80 0.6875 Total 562 138 700 315 42 357 .931 247 96 343 (To be clear, the “Open surgery” and “Nephrolithotomy” rows are carried throughout all three tables. For instance, there were 81 small stone successes when implementing the Open surgery , as found in the middle table.) Prompt for Peer Writing Assignment 3 Analyze these data using differences in conditional proportions and relative risks (mosaic plots are also encouraged, although not required!). Draft a memo that is no more than a 1.5 pages that addresses the following questions. 1. When should doctors recommend Treatment A and when should they recommend Treatment B? Justify your position using summary statistics and/or visualizations. 2. The research question is fundamentally interested in the association between treatment type {Open surgery, nephrolithotomy} and treatment outcome {success, failure}. Does kidney stone size {small, large} confound this association? Is Simpson’s paradox at play? Finally, as required by all PW essay submissions, make sure your report includes the names and NetIDs of all group members who contributed to the final product. For reference, the table below can be used, should you choose. Recitation Section 013 Peer Writing Assignment 3 Teammate 1: Julie Salerno, salern16@msu.edu Teammate 2: Landen Taber, taberla1@msu.edu Teammate 3: Adriana Owenby, owenbyad@msu.edu Teammate 4: John Torok, torokjoh@msu.edu File submissions should be in a .pdf format!