How to read a systematic Review and Meta-analysis and apply the results to patien care.

Revisión Sistematica: revisiones focalizadas en preguntas clínicas. Acompñada pero no siempre de un metaanalisis.

Credibilidad y confiabilidad.
The Process of Conducting a Systematic Review and Meta-analysis
1. Formulate the question
2. Define the eligibility criteria for studies to be included in terms of Patient, Intervention, Comparison, Outcome (PICO), and study design
3. Develop a priori hypotheses to explain heterogeneity
4. Conduct search
5. Screen titles and abstracts for inclusion
6. Review full text of possibly eligible studies
7. Assess the risk of bias
8. Abstract data
9. When meta-analysis is performed:
• Generate summary estimates and confidence intervals
• Look for explanations of heterogeneity
• Rate confidence in estimates of effect.

Guide for Appraising and Applying the Results of a Systematic Review and Meta-analysisa

First Judgment: Evaluate the Credibility of the Methods of Systematic Review

• Did the review explicitly address a sensible clinical question?

focus and address questions defined by particular patients, interventions, comparison and outcomes. the eligibility criteria did improve the poblation of study.

• Was the search for relevant studies exhaustive? 

multiple database for search, multiple synonyms for terms are needed.

• Were selection and assessments of studies reproducible?

having 2 o more reviewers participate, elegilibity por quality (statistic)

• Did the review present results that are ready for clinical application?

MA estimates of effect size (the magnitude between groups).

The form of presentation of units of results. 

Results of meta-analyses are usually depicted in a forest. The point estimate of each study is typically represents a square with a size proportional to the wight. and the IC as a horizontal line. The combined result as a diamond.  

More weight and precision 

• Did the review address confidence in estimates of effect?.

RS well conducted credible, the bias and the heterogeneity is explicated,

Second Judgment: Rate the Confidence in the Effect Estimates

What is the confidence in the estimates of effect?

GRADE system for evaluate the quality of evidence. Hig moderate, low and very low. the confidencie can low whith bias, imprecision, inconsistency.

• How serious is the risk of bias in the body of evidence?

the sistematic review should be demostrate the form of calculate the risk of bias and demostrate that is low and confidence.

• Are the results consistent across studies?
• How precise are the results?
• Do the results directly apply to my patient?
• Is there concern about reporting bias?
• Are there reasons to increase the confidence rating?

Why use systematic review and metanalysis: Representative, >confidence.  

choosing wisely

1. Don’t obtain screening exercise electrocardiogram testing in individuals who are asymptomatic and at low risk for coronary heart disease (<10% in 10 years).

2. Don’t obtain imaging studies in patients with non-specific low back pain.

3. In patients with witnessed syncope but with no suggestion of seizure and no report of other neurologic symptoms or signs, the likelihood of a central nervous system (CNS) cause of the event is extremely low and patient outcomes are not improved with brain imaging studies

4. In patients with low pretest probability of VTE as defined by the Wells prediction rules, a negative high-sensitivity D-dimer measurement effectively excludes VTE and the need for further imaging studies.

5. Don’t obtain preoperative chest radiography in the absence of a clinical suspicion for intrathoracic pathology. In the absence of cardiopulmonary symptoms, preoperative chest radiography rarely provides any meaningful changes or improve patient outcomes.

Insulin Therapy for Type 2 Diabetes Mellitus

Insulin Therapy for Type 2 Diabetes Mellitus

The hemoglobin A1c target for most patients with type 2 diabetes is 7% 

 Ismail-Beigi et al: targed approximately 8%:  Increased risk of hypoglycemia, reduced life expectancy,

extensive comorbidities (renal/liver failure- alcohol abuse), cardiovascular diseases, DM duration or reduced resources. 

Insulin adverse effects include weight gain and hypoglycemia.

Basal insulin can be added to oral hypoglycemic agents (generally stopping sulfonylureas)

initially, and later, prandial insulin can be added in a stepwise fashion. 

1. Insulin Resistance: impaired ability to suppress hepatic glucose production a peripheral glucose uptake.

2. Progressive imparirment of insulin secretion.

ACCORD HBA1c less than 6,0% more harmfull. 7,0-7.9 % less hypoglicemia and mortality. 

DCCT/EDIC  Increase in HBA1c from 7% to 8%. Results in an absolute increase from 1 event per year to only 2 events per year of retinopathy progression. 

Lower HbA1c goals: younger, not developed hypoglycemia, and when the benefits of microvascular

disease protection outweigh the risks of hypoglycemia.

 

EXTRASYSTOLE

KEY CONCEPTS OF VENTRICULAR PREMATURE BEATS. 

VPB: PREMATURE ELECTRIC ACTIVITIE. Re-entry: Increase of aumatism. Ussually with constan coupling time(re-entry).   

Exercise: to accelerate sinus rythm (overriding) VPB tend to disappear. 

Coupling time: distance from a sinus beat qrs to ectopic qrs..

Compensatory pause:  when the VPB activate the sinus node o AV node.  reset this and generate an absolute refractory period in this cells, and when returnig to contract, the RR interval that includes VPB is twice than sinusal RR intervals. 

The ventricular ES could reset the sinusal node and generate p wave and alterate the compensatory pause. 

Morphology of extrasystole V1: right bundle branch block (QRS > +) originated in VI.  Image LBBB QRS > - probably originated of right ventricle. Most positive in V1 morphology of RBBB.  Most negative in V1 morphology of LBBB 


Axis wave is more positive in superior wall. More negative originated in inferior wall.

Parasystole:  cell group with own frequency (usually more slow). Entry block. opened output tract. 
3 characteristic: variable coupling interval.
                             Interectopic long interval is multiple of interectopic short interval.
                            Fusion beat.  

Ashman phenomenon: are described as wide complex QRS complexes that follow a short R-R interval preceded by a long R-R interval.This wide QRS complex typically has a right bundle branch block morphology and represents an aberrantly conducted complex that originates above the AV node, rather than a complex that originates in either the right or left ventricle.


R/T wave phenomenon. 

SV VPB: P wave with different morpholgy of P sinusal. P originated in outup tract of right ventricle are negative in the inferior derivatives and positive in AVR.

auricular Extrasystole not conducted- Blockaded SV - ES.

Different morphology: multifocal VPB. worse pronostic.

Beginnign the trip.

Hoy al enterarme que perdí la oportunidad de condonar mi crédito educativo para el Icetex. Decido crear este blog para acompañar mi camino a una Residencia médica en Medicina interna. A estudiar y a prepararme con todas las ganas el camino es largo y no es fácil pero es una prueba a enfrentar.
Me comprometo a mantener actualizado mi blog con datos útiles para repasos y enlaces de interés y apoyo.