What type of study was this

In homeless individuals with opioid addiction (P), does the implementation of supervised injection sites (I), as compared to abstinence-promotion programs (C), lead to a more significant reduction in substance-related self-harm incidents (O) over five years (T)? This is my PICOT research question though due to contemporary nature of this topic, I am unable to find primary research articles in the databases to use for a literature Review. How can I reword or fix this PICOT question to retain more articles.

what is the design type in the following study "The cost-effectiveness of substituting physicians with diabetes nursespecialists: a randomized controlled trial with 2-year follow-up"

14:58 bip O O₂ اس اس 0 Investigators enrolled 40 diabetics without eye disease in a cohort (follow-up) study. The results of the first 3 years were as follows: Year 1:0 cases of eye disease detected out of 32; 8 lost to follow-up Year 2: 2 new cases of eye disease detected out of 28; 2 had died; 10 lost to follow-up Year 3: 3 new cases of eye disease detected out of 14; 2 more had died; 5 more lost to follow-up The person-time incidence rate is calculated as: Select one: O a. 5/65 O b. 5/72 O c. 5/85 O d. 5/90

Consumption of coffee may be a protective factor for Alzheimer’s disease.  To test this association, health and nutrition data from 60 countries around the world were obtained, and the correlation between per capita annual consumption of coffee and age-standardized incidence of Alzheimer’s disease was analyzed.  What type of study design is it?         Ecologic study     Cohort study     Case-control study     Randomized controlled trial     Quasi experimental study

In our healthcare world we use Lean and Six Sigma for Process Improvement. For example, in our company we used to Lean to decrease wait times in the ED. How do we use six-sigma in healthcare – give us a specific example?

What are five variables that might be important to include, and define the outcome for a cross-sectional study design that assesses the risk of developing type 2 diabetes among obese people?