Longitudinal table abx dose prescribed/administered feature

[peterdutey]

Longitudinal tables can currently be enriched with clinical features using clinical_features_X() functions.

Additional functions are needed for the following medication features:

1. dose administered between t_start and t_end in wide format: dose_administered_XXX
2. daily dose prescribed as of t_start in wide format: daily_dose_prescribed_XXX
3. cumulative dose administered in the last H hours: cum_dose_administered_Hh_XXX where H is set by function argument hours

where XXX is provided by drug_prescriptions.drug_code.

Antifungal and antibacterial prescription dosing is most commonly expressed in

• mass (easily convertible into grams) - this is the preferred unit
• IU (eg nystatin, colistin) - this may be accommodated by conversion functions
• number of table/capsule/etc: this may need to be disallowed by validate_prescription in future releases
• volume of solution: this may need to be disallowed by validate_prescriptions() in future releases.

In the event users need to preserve all types of units as currently possible, the alternative solution would be to introduce a mandatory dose_gram field in the drug_prescriptions schema definition.

Views are welcome - please contribute!