Pneumocystis jiroveci pneumonia prophylaxis not prescribed within 3 months of low cd4+ cell count below 500 cells/mm3 or a cd4 percentage below 15% for medical reason (i.e., patient's cd4+ cell count above threshold within 3 months after cd4+ cell count below threshold, indicating that the patient's cd4+ levels are within an acceptable range and the patient does not require pcp prophylaxis)