Download SAS 13 Midterm #1 2026 – PDF Study Guide & Practice Questions and more Exams Statistics in PDF only on Docsity!
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SAS 13 MIDTERM
- • Why might a single disease have multiple names? How could multiple names for the same disease create confusion in medicine or public health? Answer A single disease can have multiple names because it may be discovered by ditterent scientists, named after symptoms, causes, locations, or people, or renamed over time as understanding improves. This can create confusion in medicine and public health by making it harder to track cases, share research, and communicate clearly, which can lead to misdiagnosis, duplicated data, or delayed responses.
- What are the different names for Pott's Disease? How are each descriptive of the disease or its history? How does this example highlight the need for standardized disease classification systems? Answer Pott's disease - named after Percivall Pott, who first described the spinal form of tuberculosis. Spinal tuberculosis - describes the cause (tuberculosis infection) and location (spine).
2 / 100 Tuberculous spondylitis - a more technical term: "spondylitis" means inflammation of the vertebrae, and "tuberculous" identifies the infection. Vertebral TB - a shortened, modern clinical term emphasizing the same idea. Each name highlights either the history (who discovered it) or the biology and location of the disease. This example shows why standardized disease classification systems (like the World Health Organization's ICD system) are important: multiple names for the same disease can cause confusion in diagnosis, research, and reporting. Standardization ensures everyone is referring to the same condition, improving communication, data tracking, and treatment consistency.
- What does ICD stand for? What type of system is the ICD? Who publishes and maintains the ICD? What are the main uses of the ICD? Answer International Classification of Diseases A system of alphanumeric codes used to classify diseases, health conditions and related information Global standard
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- Has the U.S. transitioned to ICD-11? What is ICD-10 used for in the U.S.? What is ICD- 10 - CM used for in the U.S.? What does "CM" stand for? Which organization adapted the ICD- 10 - CM for U.S. use? Why might the ICD- 11 reduce the need for a clinical modification (CM)? Answer The UCD- 10 - CM is the U.S. modification of ICD-10 used for clinical encounters and billing (CM = Clinical modification) It is adapted by the National Center for Health Statistics (NCHS) at the CDC from the WHO ICD- 10 framework for use in the U.S. Implementation of ICD- 11 in the US is unlikely in the near future The UCD- 11 allows for more detail and flexibility in coding, potentially making a CM unnecessary
- What are "codes for special purposes"? Why are they necessary? Provide an example of their use. Answer "Codes for special purposes" are ICD codes used for new or unusual health situations that don't
5 / 100 fit normal categories. They're necessary to track emerging diseases quickly and consistently. Example: A special ICD code was created for COVID- 19 (U07.1) to monitor cases worldwide.
- • What is the main purpose of the ICD globally? How do ICD codes support data collection and comparison across countries? Answer The main purpose of the ICD (by the World Health Organization) is to standardize how diseases and health conditions are recorded worldwide. ICD codes support data collection and comparison by giving every condition a universal code, so ditterent countries can record, share, and compare health data consistently, even if they use ditterent languages or terms.
- How is ICD-10 used in the U.S.? What historical efforts led to the develop- ment of the ICD? Answer It's used to code diagnoses and causes of death, especially for medical billing, insurance claims, hospital records, and public health tracking
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- Why are diseases often classified by the body system they affect? Answer In medicine, physicians often specialize by body system and focus on diseases attecting those systems
- What does the term "etiology" mean? What are the three major categories of disease etiologies we discussed? Answer Etiology means the cause or origin of a disease. The three major categories of disease etiology are: Infectious - caused by pathogens like bacteria, viruses, or parasites Genetic - caused by inherited genes or mutations Environmental - caused by external factors such as chemicals, lifestyle, or exposure conditions
- Name the major types of infectious agents and examples of each. Answer Major types of infectious agents with examples: Bacterium - Vibrio cholerae ’Cholera
8 / 100 Fungus - Trichophyton rubrum ’Athlete's foot Virus - Orthoebolavirus ’Ebola virus disease Protist - Plasmodium falciparum ’Malaria Helminth - Ancylostoma duodenale (hookworm) ’Ancylostomiasis
- What type of genetic disease/disorder is cystic fibrosis? What gene is affect- ed in cystic fibrosis? How does this mutation affect the body? What bacteria commonly infect individuals with cystic fibrosis/how does this exacerbate their condition? Answer cystic fibrosis is a single-gene disorder caused by mutations in the CFTR gene (cystic fibrosis transmembrane conductance regulator). Thick, dehydrated mucus clogs the lungs and other organs (i.e. GI tract) Individuals with cystic fibrosis are susceptible to chronic lung infections with exopolysaccharide (slime)-producing
10 / 100 Too little of a good thing ex. too little iodine causing goiter
- What causes nutritional deficiency diseases? Answer Nutritional deficiency diseases are caused by not getting enough essential nutrients (such as vitamins, minerals, or protein) in the diet, or by the body's inability to properly absorb or use those nutrients.
- What condition can result from iodine deficiency? How does salt relate to this? Answer Iodine deficiency can lead to goiter, which is an enlargement of the thyroid gland. Salt relates to this because iodized salt (table salt with added iodine) is a common way people get enough iodine in their diet, helping prevent goiter.
- What disease is caused by vitamin C deficiency? Historically, who developed this nutrient deficiency? Why? Answer Vitamin C deficiency causes scurvy.
11 / 100 Historically, scurvy was common among sailors and explorers, especially during long sea voyages. They developed the deficiency because they had little or no access to fresh fruits and vegetables, which are the main sources of vitamin C.
- What are multifactorial diseases? What are some examples of multifactorial diseases? Answer Diseases with multiple contributing factors (infectious, genetic, environmental) Examples: cancer, asthma, diabetes, heart disease
- What does it mean to classify diseases by mortality? Why is mortality data useful for understanding disease impact? Why is mortality data insufficient for fully understanding disease impact? Answer Classifying diseases by mortality means grouping or ranking diseases based on how many deaths they cause. Why mortality data is useful: It shows which diseases are most deadly, helps public health oflcials prioritize resources,
13 / 100 Years of Life Lost (YLL) due to early death (mortality) Years Lived with Disability (YLD) due to illness or injury (morbidity) DALYs are useful because they allow comparison of very ditterent diseases by showing their total health impact, not just how many people die from them.
- What is the purpose of disability weights? How are disability weights de- termined? What is the scale used for disability weights (0-1), and what do the endpoints represent? Answer Disability weights are used to measure how severe a health condition is by showing how much it reduces a person's quality of life. They are used in calculating DALYs (Disability-Adjusted Life Years). How they are determined: They are based on surveys and studies where people (including the general public and health experts) compare ditterent health states and judge how disabling they are. Scale (0-1): 0 = perfect health (no disability) 1 = death (complete loss of health/maximum disability)
14 / 100 Values between 0 and 1 represent ditterent levels of severity, with higher numbers meaning more severe disability.
- What is the Global Burden of Disease (GBD) Study? Who originally devel- oped it and who leads it today? What is the main goal of the GBD study? Answer Mea-sures and compared the impact of diseases and health problems worldwide. First developed in the 1990s through collaboration between the world bank and the world health organization (WHO) Now led by the Institute for health metrics and evaluation (IHME) at the University of Washington with a global network of collaborators. The main goal of the GBD study is to measure and compare health problems around the world so countries can better understand what makes people sick and focus on improving health.
- How can DALYs be used to compare disease burden globally? What types of diseases cause the greatest burden in low-income countries vs. high-income countries? Answer DALYs compare disease burden globally by measuring total years of healthy life lost, combining
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- What is the difference between a symptom and a sign? Be able to identify examples of signs vs. symptoms. Why can't diseases be defined only by their signs and symptoms?Answer Symptom: noticed/reported by the patient (subjective) Pain, itchy rash Signs: noticed/measured by others, e.g. physician (objective) High blood pressure, blood cell count, rash. Diseases can't be defined only by signs and symptoms because many ditterent diseases share the same ones
- What are the two major philosophical perspectives in defining disease? How do normativists define disease? How do naturalists define disease? What are problems with each of these definitions? Answer Normative & Naturalist Normativists:
- Emphasizes the undesirability of disease and the harms and limitations they bring to patient and/or society
- Diseases are social contractions
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- Defining disease is 'Value=laden' Problem: This approach can be subjective, because cultural values change and what counts as "abnormal" can vary. Naturalists
- Require just the presence of biological dysfunction
- Normal function contributed to individual survival and reproduction
- Defining disease is an 'objective scientific matter' Problem: This view can be too strict, because it may label some harmful conditions as not diseases (or include harmless variations) if they don't clearly involve dysfunction.
- What does "etymology" mean? Answer the study of the origins of words
- What is the origin of the word "disease"? Measles? Malaria? Answer Disease: Early 14th century, from the old French 'desaise' = "discomfort", from des- = "lack of" + aise = "ease" Measles:
19 / 100 For example, Covid was associated with china ’asian hate crimes rose after pandemic In 2021, the WHO decided that COVID variants should be named after Greek letters to help avoid discrimination based of places where disease was identifying
- What is an eponym? Why can they be problematic as disease names? Answer a person after whom a discovery, invention, place, etc., is named or thought to be named. Often do not tell the whole story about the disease discovery Ethical issues, confusing
- What are the defining features of ME/CFS? What is known about its cause (etiology)? Is there a specific diagnostic test for ME/CFS? What does "diagnosis of exclusion" mean? What are the required symptoms for diagnosis? What additional symptoms may also be present? Answer Extreme fatigue unrelieved by rest that worsens with physical or mental activity. Cause not
20 / 100 identified (unknown etiology). No diagnostic test available. Diagnosis of exclusion: This means ME/CFS is diagnosed only after other possible medical conditions have been ruled out (such as thyroid disease, anemia, sleep disorders, etc.). Symptoms: All 3 of the following required for diagnosis: Impaired function accompanied by fatigue > 6 mo. Post-exertional malaise (PEM); "crash" Unrefreshing sleep And at least one of the following required for diagnosis: Cognitive impairment; "brain fog" Orthostatic intolerance (1 Ex. = POTS) Not required for diagnosis, but common: Headaches Muscle pain (myalgia)
