Ambulatory Care Provided by Office-Based Specialists in the United States

Jose M. Valderas; Barbara Starfield; Christopher B. Forrest; Bonnie Sibbald; Martin Roland

doi:10.1370/afm.949

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Table 1.

Classification Of Visit Type: Previous Knowledge of the Health Problem

		Episode of Care (C)
New Patient (A)	Major Reason for This Visit (B)	Initial Visit for Problem	Any Other Response
Note: For example, a visit by a known patient (A) seeking care for an acute problem (B) for the first time (C) would be categorized as known patient, new problem. These categories were applied to both primary care and non–primary care visits, but the focus of the subsequent analyses is restricted to non–primary care visits only.
Yes	Acute problem	New patient	New patient
	Pre- or post-surgery	New patient	New patient
	Chronic problem, flare-up	New patient	New patient
	Chronic problem, routine	New patient	New patient
	Preventive care	New patient	New patient
	Missing	Other	Other
No	Acute problem	Known patient, new problem	Known patient, new problem
	Pre- or post-surgery	Known patient, new problem	Known patient, new problem
	Chronic problem, flare-up	Known patient, new problem	Known patient, known problem (recurrence)
	Chronic problem, routine	Known patient, new problem	Known patient, known problem (routine or preventive)
	Preventive care	Known patient, new problem	Known patient, known problem (routine or preventive)
	Missing	Other	Other

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Table 2.

Descriptives of Selected Variables for All Visits

Variable	Medical Specialists	Surgical Specialists	Obstetrician- gynecologists	Psychiatrists	Total
ADG: aggregated diagnosis group; CI = confidence interval; SCHIP = State Children’s Health Insurance Program.
Note: All differences across specialists (medical specialists vs obstetrician-gynecologists vs psychiatrists vs surgical specialists) were statistically significant at the defined α = .05 for all variables.
All visits, No. (%)	466,116,941 (36.5)	515,694,813 (40.3)	215,791,181 (16.9)	80,962,250 (6.3)	1,278,565,185 (100.0)
Sex, No. (%)
Female	260,235,334 (55.8)	280,335,293 (54.4)	215,106,923 (99.7)	43,692,472 (54.0)	799,370,022 (62.5)
Male	205,881,607 (44.2)	235,359,520 (45.6)	684,258 (0.3)	37,269,778 (46.0)	479,195,163 (37.5)
Age, mean (95% CI), y	53.5 (51.7–55.2)	53.3 (52.3–54.3)	35.8 (35.6–37.0)	39.2 (37.2–41.3)	49.51 (48.6–50.4)
Ethnicity, No. (%)
White, non-Hispanic	383,527,745 (82.3)	420,962,462 (81.6)	152,905,921 (70.9)	69,279,960(85.6)	1,026,676,088 (80.3)
Black, non-Hispanic	34,902,735 (7.5)	41,007,894 (8.0)	29,297,265 (13.6)	5,632,784 (7.0)	110,840,678 (8.7)
Hispanic	30,995,603 (6.6)	39,971,646 (7.8)	26,444,488 (12.3)	4,406,438 (5.4)	101,818,175 (8.0)
Asian/Pacific Islander	16,690,858 (3.6)	13,752,811 (2.7)	7,143,507 (3.3)	1,643,068 (2.0)	39,230,244 (3.1)
Insurance, No. (%)
Private insurance	260,900,082 (57.73)	287,431,802 (57.59)	162,188,063 (77.03)	41,598,513 (52.89)	752,118,460 (60.65)
Medicare	153,379,107 (33.94)	156,063,868 (31.27)	8,701,472 (4.13)	9,169,539 (11.66)	327,313,986 (26.39)
Medicaid/SCHIP	23,882,076 (5.28)	27,827,889 (5.58)	31,535,961 (14.98)	11,034,035 (14.03)	94,279,961 (7.60)
No insurance	13,765,906 (3.05)	27,743,946 (5.56)	8,113,992 (3.85)	16,854,687 (21.43)	66,478,531 (5.36)
Past visits, No. (%)
0	30,507,057 (8.08)	45,157,061 (11.17)	25,658,382 (13.30)	644,906 (0.87)	101,967,406 (9.72)
1–2	137,679,845 (36.46)	166,055,503 (41.08)	65,934,794 (34.18)	11,729,626 (15.74)	381,399,768 (36.35)
3–5	109,252,095 (28.93)	120,902,884 (29.91)	41,004,888 (21.25)	18,993,777 (25.49)	290,153,644 (27.65)
6 or more	100,168,775 (26.53)	72,066,951 (17.83)	60,333,886 (31.27)	43,142,388 (57.90)	275,712,000 (26.28)
Time spent with physician, mean (95% CI), min	19.4 (18.3–20.4)	17.5 (16.8–18.3)	17.3 (16.4–18.2)	33.1 (31.1–35.1)	19.2 (18.6–19.7)
Major ADG as primary diagnosis, No. (%)
Yes	129,973,814 (27.9)	86,812,987 (16.8)	2,189,475 (1.0)	37,648,031 (46.5)	256,624,307 (20.1)
No	336,143,127 (72.1)	428,881,826 (83.2)	213,601,706 (99.0	43,314,219 (53.5)	1,021,940,878 (79.9)
Number of diagnoses, mean (95% CI)	1.81 (1.76–1.87)	1.62 (1.59–1.65)	1.36 (1.31–1.41)	1.56 (1.48–1.63)	1.64 (1.61–1.67)
Visit orientation, No. (%)
Primary care	49,384,112 (10.6)	19,706,986 (3.8)	40,442,490 (18.7)	2,979,065 (3.7)	112,512,653 (8.8)
Specialty care	416,732,829 (89.4)	495,987,827 (96.2)	175,348,691 (82.3)	77,983,185 (96.3)	1,166,052,532 (91.2)

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Table 3.

Types of Visits and Frequency of Reappointments by Physician Specialty (Specialty Care Visits Only)

Visit Characteristics	Medical Specialists No. (%)	Surgical Specialists No. (%)	Obstetrician- Gynecologists No. (%)	Psychiatrists No. (%)	All Visits No. (%)
Note: All overall differences between specialties statistically significant at the defined α = .05. All differences for referred and not referred visits statistically significant for all types of visits, shared care, and reappointments, except for reappointments for medical specialist and psychiatrists.
Type of visit
New patient
Referred	50,432,210 (38.2)	70,200,541 (38.5)	7,759,568 (33.6)	3,193,437 (18.9)	13,1585,756 (37.2)
Not referred	30,923,570 (10.9)	32,540,316 (10.4)	11,682,421 (7.7)	2,644,147 (4.3)	77,790,454 (9.6)
Overall	81,355,780 (19.5)	102,740,857 (20.7)	19,441,989 (11.1)	5,837,584 (7.5)	209,376,210 (18.0)
Known patient, new problem
Referred	20,949,555 (15.9)	62,697,838 (34.4)	4,183,533 (18.1)	1,615,124 (9.6)	8,944,6050 (25.3)
Not referred	55,484,409 (19.5)	135,564,474 (43.3)	31,519,810 (20.7)	1,791,859 (2.9)	224,360,552 (27.6)
Overall	76,433,964 (18.3)	198,262,312 (40.0)	35,703,343 (20.4)	3,406,983 (4.4)	313,806,602 (26.9)
Known patient, known problem: recurrence
Referred	9,040,755 (6.9)	9,989,434 (5.5)	506,161 (2.2)	1,739,320 (10.3)	2,1275,670 (6.0)
Not referred	23,842,104 (8.4)	23,568,943 (7.5)	3,543,953 (2.3)	7,786,750 (12.7)	5,8741,750 (7.2)
Overall	32,882,859 (7.9)	33,558,377 (6.8)	4,050,114 (2.3)	9,526,070 (12.2)	8,0017,420 (6.9)
Known patient, known problem, routine or preventive
Referred	50,241,347 (38.1)	36,542,497 (20.0)	9,585,362 (41.5)	10,167,954 (60.2)	10,6537,160 (30.1)
Not referred	168,094,186 (59.0)	115,099,839 (36.7)	103,209,997 (67.8)	47,337,068 (77.5)	433,741,090 (53.4)
Overall	218,335,533 (52.4)	151,642,336 (30.6)	112,795,359 (64.3)	57,505,022 (73.7)	540,278,250 (46.3)
Other
Referred	1,266,203 (1.0)	2,836,052 (1.6)	1,058,081 (4.6)	170,351 (1.0)	5,330,687 (1.5)
Not referred	6,458,490 (2.3)	6,947,893 (2.2)	2,299,805 (1.5)	1,537,175 (2.5)	17,243,363 (2.1)
Overall	7,724,693 (1.9)	9,783,945 (2.0)	3,357,886 (1.9)	1,707,526 (2.2)	22,574,050 (1.9)
Shared care
Referred	72,734,619 (56.0)	83,164,843 (46.4)	7,942,808 (37.4)	3,697,267 (22.3)	167,711,222 (48.0)
Not referred	78,080,308 (28.1)	65,704,184 (21.4)	33,472,995 (22.5)	8,289,358 (14.0)	186,378,057 (23.2)
Overall	150,814,927 (37.0)	148,869,027 (30.7)	41,415,803 (24.3)	11,986,625 (15.8)	354,089,279 (30.7)
Reappointments
Referred	96,390,830 (73.1)	124,589,758 (68.4)	13,434,294 (58.2)	15,426,153 (91.4)	250,997,151 (70.6)
Not referred	217,382,015 (76.3)	226,893,374 (72.3)	107,602,751 (70.7)	56,909,990 (93.1)	617,375,536 (75.1)
Overall	313,772,845 (75.3)	351,483,132 (70.9)	121,037,045 (69.0)	72,336,143 (92.8)	858,629,165 (73.6)
Overall
Referred	131,930,070 (100)	182,266,362 (100)	23,092,705 (100)	16,886,186 (100)	354,175,323 (100)
Not referred	284,802,759 (100)	313,721,465 (100)	152,255,986 (100)	61,096,999 (100)	811,877,209 (100)
Overall	416,732,829 (100)	495,987,827 (100)	175,348,691 (100)	77,983,185 (100)	1,166,052,532 (100)

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Table 4.

Likelihood of Shared Care: Multiple Logistic Regression Analysis

Variables, Categories	Odds Ratio	95% CI
ADG=aggregated diagnosis group.
Note: Response category is “No.”
Specialty
Medical specialists	Reference	Reference
Surgical specialists	0.73	0.60–0.89
Obstetrician-gynecologists	0.78	0.51–1.19
Psychiatrists	0.38	0.26–0.56
Referral status
Not referred	Reference	Reference
Referred	2.99	2.52–3.55
Morbidity burden
No major ADG	Reference	Reference
Major ADG	1.39	1.21–1.61
Sex
Female	Reference	Reference
Male	0.96	0.89–1.04
Ethnicity
White, non-Hispanic	Reference	Reference
Black, non-Hispanic	1.00	0.85–1.19
Hispanic	1.35	1.08–1.68
Asian/Pacific Islander	1.63	1.08–2.45
Insurance
Private insurance	Reference	Reference
Medicare	0.95	0.83–1.08
Medicaid	1.05	0.85–1.30
No insurance	0.55	0.44–0.68
Age
0–17 y	Reference	Reference
18–64 y	1.19	1.001–1.41
≥65 y	1.39	1.14–1.69

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Table 5.

Likelihood of Reappointment: Multiple Logistic Regression Analysis

Variables, Categories	Odds Ratio	95% CI
ADG=aggregated diagnosis group.
Note: Response category is “No.
Specialty
Medical specialists	Reference	Reference
Surgical specialists	0.85	0.71–1.02
Obstetrician-gynecologists	0.87	0.63–1.19
Psychiatrists	4.36	3.18–5.97
Referral status
Not referred	Reference	Reference
Referred	0.80	0.70–0.91
Morbidity burden
No major ADG	Reference	Reference
Major ADG	1.54	1.35–1.76
Sex
Female	Reference	Reference
Male	1.07	0.999–1.14
Ethnicity
White, non-Hispanic	Reference	Reference
Black, non-Hispanic	1.03	0.85–1.26
Hispanic	1.02	0.87–1.19
Asian/Pacific Islander	1.15	0.88–1.51
Insurance
Private insurance	Reference	Reference
Medicare	1.32	1.18–1.48
Medicaid	1.41	1.16–1.70
No insurance	0.74	0.62–0.89
Age
0–17 years	Reference	Reference
18–64 years	1.07	0.90–1.26
≥65 years	1.23	0.997–1.53

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The Article in Brief

Ambulatory Care Provided by Office-Based Specialists in the United States

Jose M. Valderas and colleagues

Background There are conflicting opinions about whether the United States needs more medical specialists. To help inform the debate, this study describes the nature and content of specialist care provided in community settings.

What This Study Found One-half of visits to specialists were for routine and preventive care for patients already known to the doctor, and most of these visits resulted in a follow-up appointment. Less than one-third of all specialty care visits were the result of a referral from another health care professional.

Implications

Many services provided by specialists could be managed in primary care settings. This would reduce demand for specialists and improve coordination of care.
Having the primary care doctor do follow-up care would be more efficient and would allow specialists to focus on those aspects of care which demand their unique skills.