Two common presenting symptoms (low back pain and neck pain) and 3 medical diagnoses (upper respiratory infection, hypertension, and diabetes mellitus) served as the basis for this study. Low back pain consisted of NAMCS primary reason for visit (RFV) codes 1905.0 through 1905.5 (relating to back pain) and 1910.0 through 1910.5 (relating to low back pain), which included the terms “pain, ache, soreness, discomfort, cramps, contractures, spasms, limitation of movement, stiffness, weakness, or swelling.” Patient visits involving a lump, mass, or tumor were excluded. Neck pain consisted of RFV codes 1900.0 through 1900.5, which also included the terms listed above for low back pain and excluded visits involving a lump, mass, or tumor. Upper respiratory infection consisted of RFV codes 1445.0 (head cold) and 1400.0 (nasal congestion). The latter included the terms “drippy nose, excess mucus, nasal obstruction, post-nasal drip, runny nose, sniffles, and stuffy nose.” Hypertension consisted of RFV code 2510.0, which excluded hypertension diagnoses with target organ involvement, such as hypertensive heart disease, pulmonary hypertension, and renal hypertension. Diabetes mellitus consisted of RFV code 2205.0, which included both type 1 and type 2 diabetes mellitus.